Add version 4.2 to all existing migrations

DB schema generated by a migration may look different in
rails 4 and 5 (because rails 5 may use different default values).
For this reason it's important to explicitly set for which rails
version a migration was written for.

See https://stackoverflow.com/questions/35929869/activerecordmigration-deprecation-warning-asks-for-rails-version-but-im-no/35930912#35930912

db/migrate/20140313092127_init_schema.rb

-class InitSchema < ActiveRecord::Migration
+class InitSchema < ActiveRecord::Migration[4.2]
   DOWNTIME = true
 
   # rubocop:disable Metrics/AbcSize

db/migrate/20140407135544_fix_namespaces.rb

-class FixNamespaces < ActiveRecord::Migration
+class FixNamespaces < ActiveRecord::Migration[4.2]
   DOWNTIME = false
 
   def up

db/migrate/20140414131055_change_state_to_allow_empty_merge_request_diffs.rb

 # rubocop:disable all
-class ChangeStateToAllowEmptyMergeRequestDiffs < ActiveRecord::Migration
+class ChangeStateToAllowEmptyMergeRequestDiffs < ActiveRecord::Migration[4.2]
   def up
     change_column :merge_request_diffs, :state, :string, null: true,
                   default: nil

db/migrate/20140416074002_add_index_on_iid.rb

 # rubocop:disable all
-class AddIndexOnIid < ActiveRecord::Migration
+class AddIndexOnIid < ActiveRecord::Migration[4.2]
   def change
     RemoveDuplicateIid.clean(Issue)
     RemoveDuplicateIid.clean(MergeRequest, 'target_project_id')

db/migrate/20140416185734_index_on_current_sign_in_at.rb

 # rubocop:disable all
-class IndexOnCurrentSignInAt < ActiveRecord::Migration
+class IndexOnCurrentSignInAt < ActiveRecord::Migration[4.2]
   def change
     add_index :users, :current_sign_in_at
   end

db/migrate/20140428105831_add_notes_index_updated_at.rb

 # rubocop:disable all
-class AddNotesIndexUpdatedAt < ActiveRecord::Migration
+class AddNotesIndexUpdatedAt < ActiveRecord::Migration[4.2]
   def change
     add_index :notes, :updated_at
   end

db/migrate/20140502115131_add_repo_size_to_db.rb

 # rubocop:disable all
-class AddRepoSizeToDb < ActiveRecord::Migration
+class AddRepoSizeToDb < ActiveRecord::Migration[4.2]
   def change
     add_column :projects, :repository_size, :float, default: 0
   end

db/migrate/20140502125220_migrate_repo_size.rb

 # rubocop:disable all
-class MigrateRepoSize < ActiveRecord::Migration
+class MigrateRepoSize < ActiveRecord::Migration[4.2]
   DOWNTIME = false
 
   def up

db/migrate/20140611135229_add_position_to_merge_request.rb

 # rubocop:disable all
-class AddPositionToMergeRequest < ActiveRecord::Migration
+class AddPositionToMergeRequest < ActiveRecord::Migration[4.2]
   def change
     add_column :merge_requests, :position, :integer, default: 0
   end

db/migrate/20140625115202_create_users_star_projects.rb

 # rubocop:disable all
-class CreateUsersStarProjects < ActiveRecord::Migration
+class CreateUsersStarProjects < ActiveRecord::Migration[4.2]
   DOWNTIME = false
 
   def change

db/migrate/20140729134820_create_labels.rb

 # rubocop:disable all
-class CreateLabels < ActiveRecord::Migration
+class CreateLabels < ActiveRecord::Migration[4.2]
   DOWNTIME = false
 
   def change

db/migrate/20140729140420_create_label_links.rb

 # rubocop:disable all
-class CreateLabelLinks < ActiveRecord::Migration
+class CreateLabelLinks < ActiveRecord::Migration[4.2]
   DOWNTIME = false
 
   def change

db/migrate/20140729145339_migrate_project_tags.rb

-class MigrateProjectTags < ActiveRecord::Migration
+class MigrateProjectTags < ActiveRecord::Migration[4.2]
   def up
     ActsAsTaggableOn::Tagging.where(taggable_type: 'Project', context: 'labels').update_all(context: 'tags')
   end

db/migrate/20140729152420_migrate_taggable_labels.rb

 # rubocop:disable all
-class MigrateTaggableLabels < ActiveRecord::Migration
+class MigrateTaggableLabels < ActiveRecord::Migration[4.2]
   def up
     taggings = ActsAsTaggableOn::Tagging.where(taggable_type: ['Issue', 'MergeRequest'], context: 'labels')
     taggings.find_each(batch_size: 500) do |tagging|

db/migrate/20140730111702_add_index_to_labels.rb

 # rubocop:disable all
-class AddIndexToLabels < ActiveRecord::Migration
+class AddIndexToLabels < ActiveRecord::Migration[4.2]
   def change
     add_index "labels", :project_id
     add_index "label_links", :label_id

db/migrate/20140903115954_migrate_to_new_shell.rb

 # rubocop:disable all
-class MigrateToNewShell < ActiveRecord::Migration
+class MigrateToNewShell < ActiveRecord::Migration[4.2]
   def change
     return if Rails.env.test?
 

db/migrate/20140907220153_serialize_service_properties.rb

 # rubocop:disable all
-class SerializeServiceProperties < ActiveRecord::Migration
+class SerializeServiceProperties < ActiveRecord::Migration[4.2]
   def change
     unless column_exists?(:services, :properties)
       add_column :services, :properties, :text

db/migrate/20140914113604_add_members_table.rb

 # rubocop:disable all
-class AddMembersTable < ActiveRecord::Migration
+class AddMembersTable < ActiveRecord::Migration[4.2]
   DOWNTIME = false
 
   def change

db/migrate/20140914145549_migrate_to_new_members_model.rb

 # rubocop:disable all
-class MigrateToNewMembersModel < ActiveRecord::Migration
+class MigrateToNewMembersModel < ActiveRecord::Migration[4.2]
   def up
     execute "INSERT INTO members ( user_id, source_id, source_type, access_level, notification_level, type ) SELECT user_id, group_id, 'Namespace', group_access, notification_level, 'GroupMember' FROM users_groups"
     execute "INSERT INTO members ( user_id, source_id, source_type, access_level, notification_level, type ) SELECT user_id, project_id, 'Project', project_access, notification_level, 'ProjectMember' FROM users_projects"

db/migrate/20140914173417_remove_old_member_tables.rb

 # rubocop:disable all
-class RemoveOldMemberTables < ActiveRecord::Migration
+class RemoveOldMemberTables < ActiveRecord::Migration[4.2]
   DOWNTIME = false
 
   def up

db/migrate/20141006143943_move_slack_service_to_webhook.rb

 # rubocop:disable all
-class MoveSlackServiceToWebhook < ActiveRecord::Migration
+class MoveSlackServiceToWebhook < ActiveRecord::Migration[4.2]
 
   DOWNTIME = true
   DOWNTIME_REASON = 'Move old fields "token" and "subdomain" to one single field "webhook"'

db/migrate/20141007100818_add_visibility_level_to_snippet.rb

 # rubocop:disable all
-class AddVisibilityLevelToSnippet < ActiveRecord::Migration
+class AddVisibilityLevelToSnippet < ActiveRecord::Migration[4.2]
   include Gitlab::Database::MigrationHelpers
 
   def up

db/migrate/20141118150935_add_audit_event.rb

 # rubocop:disable all
-class AddAuditEvent < ActiveRecord::Migration
+class AddAuditEvent < ActiveRecord::Migration[4.2]
   DOWNTIME = false
 
   def change

db/migrate/20141121133009_add_timestamps_to_members.rb

@@ -3,7 +3,7 @@
 # became a problem after commit c8e78d972a5a628870eefca0f2ccea0199c55bda which
 # was added in GitLab 7.5. With this migration we ensure that all rows in
 # 'members' have at least some created_at and updated_at timestamp.
-class AddTimestampsToMembers < ActiveRecord::Migration
+class AddTimestampsToMembers < ActiveRecord::Migration[4.2]
   def up
     execute "UPDATE members SET created_at = NOW() WHERE created_at is NULL"
     execute "UPDATE members SET updated_at = NOW() WHERE updated_at is NULL"

db/migrate/20141121161704_add_identity_table.rb

 # rubocop:disable all
-class AddIdentityTable < ActiveRecord::Migration
+class AddIdentityTable < ActiveRecord::Migration[4.2]
   def up
     create_table :identities do |t|
       t.string :extern_uid

db/migrate/20141126120926_add_merge_request_rebase_enabled_to_projects.rb

 # rubocop:disable all
-class AddMergeRequestRebaseEnabledToProjects < ActiveRecord::Migration
+class AddMergeRequestRebaseEnabledToProjects < ActiveRecord::Migration[4.2]
   include Gitlab::Database::MigrationHelpers
 
   # Set this constant to true if this migration requires downtime.

db/migrate/20141205134006_add_locked_at_to_merge_request.rb

 # rubocop:disable all
-class AddLockedAtToMergeRequest < ActiveRecord::Migration
+class AddLockedAtToMergeRequest < ActiveRecord::Migration[4.2]
   def change
     add_column :merge_requests, :locked_at, :datetime
   end

db/migrate/20141216155758_create_doorkeeper_tables.rb

 # rubocop:disable all
-class CreateDoorkeeperTables < ActiveRecord::Migration
+class CreateDoorkeeperTables < ActiveRecord::Migration[4.2]
   DOWNTIME = false
 
   def change

db/migrate/20141217125223_add_owner_to_application.rb

 # rubocop:disable all
-class AddOwnerToApplication < ActiveRecord::Migration
+class AddOwnerToApplication < ActiveRecord::Migration[4.2]
   def change
     add_column :oauth_applications, :owner_id, :integer, null: true
     add_column :oauth_applications, :owner_type, :string, null: true

db/migrate/20141223135007_add_import_data_to_project_table.rb

-class AddImportDataToProjectTable < ActiveRecord::Migration
+class AddImportDataToProjectTable < ActiveRecord::Migration[4.2]
   def change
     add_column :projects, :import_type, :string
     add_column :projects, :import_source, :string

db/migrate/20141226080412_add_developers_can_push_to_protected_branches.rb

 # rubocop:disable all
-class AddDevelopersCanPushToProtectedBranches < ActiveRecord::Migration
+class AddDevelopersCanPushToProtectedBranches < ActiveRecord::Migration[4.2]
   def change
     add_column :protected_branches, :developers_can_push, :boolean, default: false, null: false
   end

db/migrate/20150108073740_create_application_settings.rb

 # rubocop:disable all
-class CreateApplicationSettings < ActiveRecord::Migration
+class CreateApplicationSettings < ActiveRecord::Migration[4.2]
   DOWNTIME = false
 
   def change

db/migrate/20150116234544_add_home_page_url_for_application_settings.rb

-class AddHomePageUrlForApplicationSettings < ActiveRecord::Migration
+class AddHomePageUrlForApplicationSettings < ActiveRecord::Migration[4.2]
   def change
     add_column :application_settings, :home_page_url, :string
   end

db/migrate/20150116234545_add_gitlab_access_token_to_user.rb

-class AddGitlabAccessTokenToUser < ActiveRecord::Migration
+class AddGitlabAccessTokenToUser < ActiveRecord::Migration[4.2]
   def change
     add_column :users, :gitlab_access_token, :string
   end

db/migrate/20150125163100_add_default_branch_protection_setting.rb

 # rubocop:disable all
-class AddDefaultBranchProtectionSetting < ActiveRecord::Migration
+class AddDefaultBranchProtectionSetting < ActiveRecord::Migration[4.2]
   def change
     add_column :application_settings, :default_branch_protection, :integer, :default => 2
   end

db/migrate/20150205211843_add_timestamps_to_identities.rb

 # rubocop:disable all
-class AddTimestampsToIdentities < ActiveRecord::Migration
+class AddTimestampsToIdentities < ActiveRecord::Migration[4.2]
   def change
     add_timestamps(:identities)
   end

db/migrate/20150206181414_add_index_to_created_at.rb

 # rubocop:disable all
-class AddIndexToCreatedAt < ActiveRecord::Migration
+class AddIndexToCreatedAt < ActiveRecord::Migration[4.2]
   def change
     add_index "users", [:created_at, :id]
     add_index "members", [:created_at, :id]

db/migrate/20150206222854_add_notification_email_to_user.rb

-class AddNotificationEmailToUser < ActiveRecord::Migration
+class AddNotificationEmailToUser < ActiveRecord::Migration[4.2]
   def up
     add_column :users, :notification_email, :string
 

db/migrate/20150209222013_add_missing_index.rb

 # rubocop:disable all
-class AddMissingIndex < ActiveRecord::Migration
+class AddMissingIndex < ActiveRecord::Migration[4.2]
   def change
     add_index "services", [:created_at, :id]
   end

db/migrate/20150211172122_add_template_to_service.rb

 # rubocop:disable all
-class AddTemplateToService < ActiveRecord::Migration
+class AddTemplateToService < ActiveRecord::Migration[4.2]
   def change
     add_column :services, :template, :boolean, default: false
   end

db/migrate/20150211174341_allow_null_in_services_project_id.rb

-class AllowNullInServicesProjectId < ActiveRecord::Migration
+class AllowNullInServicesProjectId < ActiveRecord::Migration[4.2]
   def change
     change_column :services, :project_id, :integer, null: true
   end

db/migrate/20150213104043_add_twitter_sharing_enabled_to_application_settings.rb

 # rubocop:disable all
-class AddTwitterSharingEnabledToApplicationSettings < ActiveRecord::Migration
+class AddTwitterSharingEnabledToApplicationSettings < ActiveRecord::Migration[4.2]
   def change
     add_column :application_settings, :twitter_sharing_enabled, :boolean, default: true
   end

db/migrate/20150213114800_add_hide_no_password_to_user.rb

 # rubocop:disable all
-class AddHideNoPasswordToUser < ActiveRecord::Migration
+class AddHideNoPasswordToUser < ActiveRecord::Migration[4.2]
   def change
     add_column :users, :hide_no_password, :boolean, default: false
   end

db/migrate/20150213121042_add_password_automatically_set_to_user.rb

 # rubocop:disable all
-class AddPasswordAutomaticallySetToUser < ActiveRecord::Migration
+class AddPasswordAutomaticallySetToUser < ActiveRecord::Migration[4.2]
   def change
     add_column :users, :password_automatically_set, :boolean, default: false
   end

db/migrate/20150217123345_add_bitbucket_access_token_and_secret_to_user.rb

-class AddBitbucketAccessTokenAndSecretToUser < ActiveRecord::Migration
+class AddBitbucketAccessTokenAndSecretToUser < ActiveRecord::Migration[4.2]
   def change
     add_column :users, :bitbucket_access_token, :string
     add_column :users, :bitbucket_access_token_secret, :string

db/migrate/20150219004514_add_events_to_services.rb

 # rubocop:disable all
-class AddEventsToServices < ActiveRecord::Migration
+class AddEventsToServices < ActiveRecord::Migration[4.2]
   def change
     add_column :services, :push_events, :boolean, :default => true
     add_column :services, :issues_events, :boolean, :default => true

db/migrate/20150223022001_set_missing_last_activity_at.rb

-class SetMissingLastActivityAt < ActiveRecord::Migration
+class SetMissingLastActivityAt < ActiveRecord::Migration[4.2]
   def up
     execute "UPDATE projects SET last_activity_at = updated_at WHERE last_activity_at IS NULL"
   end

db/migrate/20150225065047_add_note_events_to_services.rb

 # rubocop:disable all
-class AddNoteEventsToServices < ActiveRecord::Migration
+class AddNoteEventsToServices < ActiveRecord::Migration[4.2]
   def change
     add_column :services, :note_events, :boolean, default: true, null: false
   end

db/migrate/20150301014758_add_restricted_visibility_levels_to_application_settings.rb

-class AddRestrictedVisibilityLevelsToApplicationSettings < ActiveRecord::Migration
+class AddRestrictedVisibilityLevelsToApplicationSettings < ActiveRecord::Migration[4.2]
   def change
     add_column :application_settings, :restricted_visibility_levels, :text
   end

db/migrate/20150306023106_fix_namespace_duplication.rb

 # rubocop:disable all
-class FixNamespaceDuplication < ActiveRecord::Migration
+class FixNamespaceDuplication < ActiveRecord::Migration[4.2]
   def up
     #fixes path duplication
     select_all('SELECT MAX(id) max, COUNT(id) cnt, path FROM namespaces GROUP BY path HAVING COUNT(id) > 1').each do |nms|

db/migrate/20150306023112_add_unique_index_to_namespace.rb

 # rubocop:disable all
-class AddUniqueIndexToNamespace < ActiveRecord::Migration
+class AddUniqueIndexToNamespace < ActiveRecord::Migration[4.2]
   def change
     remove_index :namespaces, column: :name if index_exists?(:namespaces, :name)
     remove_index :namespaces, column: :path if index_exists?(:namespaces, :path)

db/migrate/20150310194358_add_version_check_to_application_settings.rb

 # rubocop:disable all
-class AddVersionCheckToApplicationSettings < ActiveRecord::Migration
+class AddVersionCheckToApplicationSettings < ActiveRecord::Migration[4.2]
   def change
     add_column :application_settings, :version_check_enabled, :boolean, default: true
   end

db/migrate/20150313012111_create_subscriptions_table.rb

 # rubocop:disable all
-class CreateSubscriptionsTable < ActiveRecord::Migration
+class CreateSubscriptionsTable < ActiveRecord::Migration[4.2]
   DOWNTIME = false
 
   def change

db/migrate/20150320234437_add_location_to_user.rb

-class AddLocationToUser < ActiveRecord::Migration
+class AddLocationToUser < ActiveRecord::Migration[4.2]
   def change
     add_column :users, :location, :string
   end

db/migrate/20150324155957_set_incorrect_assignee_id_to_null.rb

-class SetIncorrectAssigneeIdToNull < ActiveRecord::Migration
+class SetIncorrectAssigneeIdToNull < ActiveRecord::Migration[4.2]
   def up
     execute "UPDATE issues SET assignee_id = NULL WHERE assignee_id = -1"
     execute "UPDATE merge_requests SET assignee_id = NULL WHERE assignee_id = -1"

db/migrate/20150327122227_add_public_to_key.rb

 # rubocop:disable all
-class AddPublicToKey < ActiveRecord::Migration
+class AddPublicToKey < ActiveRecord::Migration[4.2]
   def change
     add_column :keys, :public, :boolean, default: false, null: false
   end

db/migrate/20150327150017_add_import_data_to_project.rb

-class AddImportDataToProject < ActiveRecord::Migration
+class AddImportDataToProject < ActiveRecord::Migration[4.2]
   def change
     add_column :projects, :import_data, :text
   end

db/migrate/20150327223628_add_devise_two_factor_to_users.rb

-class AddDeviseTwoFactorToUsers < ActiveRecord::Migration
+class AddDeviseTwoFactorToUsers < ActiveRecord::Migration[4.2]
   def change
     add_column :users, :encrypted_otp_secret, :string
     add_column :users, :encrypted_otp_secret_iv, :string

db/migrate/20150328132231_add_max_attachment_size_to_application_settings.rb

-class AddMaxAttachmentSizeToApplicationSettings < ActiveRecord::Migration
+class AddMaxAttachmentSizeToApplicationSettings < ActiveRecord::Migration[4.2]
   def change
     add_column :application_settings, :max_attachment_size, :integer, default: 10, null: false
   end

db/migrate/20150331183602_add_devise_two_factor_backupable_to_users.rb

-class AddDeviseTwoFactorBackupableToUsers < ActiveRecord::Migration
+class AddDeviseTwoFactorBackupableToUsers < ActiveRecord::Migration[4.2]
   def change
     add_column :users, :otp_backup_codes, :text
   end

db/migrate/20150406133311_add_invite_data_to_member.rb

 # rubocop:disable all
-class AddInviteDataToMember < ActiveRecord::Migration
+class AddInviteDataToMember < ActiveRecord::Migration[4.2]
   def up
     add_column :members, :created_by_id, :integer
     add_column :members, :invite_email, :string

db/migrate/20150411000035_fix_identities.rb

-class FixIdentities < ActiveRecord::Migration
+class FixIdentities < ActiveRecord::Migration[4.2]
   def up
     # Up until now, legacy 'ldap' references in the database were charitably
     # interpreted to point to the first LDAP server specified in the GitLab

db/migrate/20150411180045_rename_buildbox_service.rb

-class RenameBuildboxService < ActiveRecord::Migration
+class RenameBuildboxService < ActiveRecord::Migration[4.2]
   def up
     execute "UPDATE services SET type = 'BuildkiteService' WHERE type = 'BuildboxService';"
   end

db/migrate/20150413192223_add_public_email_to_users.rb

 # rubocop:disable all
-class AddPublicEmailToUsers < ActiveRecord::Migration
+class AddPublicEmailToUsers < ActiveRecord::Migration[4.2]
   def change
     add_column :users, :public_email, :string, default: "", null: false
   end

db/migrate/20150417121913_create_project_import_data.rb

-class CreateProjectImportData < ActiveRecord::Migration
+class CreateProjectImportData < ActiveRecord::Migration[4.2]
   def change
     create_table :project_import_data do |t|
       t.references :project

db/migrate/20150417122318_remove_import_data_from_project.rb

 # rubocop:disable all
-class RemoveImportDataFromProject < ActiveRecord::Migration
+class RemoveImportDataFromProject < ActiveRecord::Migration[4.2]
   def up
     remove_column :projects, :import_data
   end

db/migrate/20150421120000_remove_periods_at_ends_of_usernames.rb

 # rubocop:disable all
-class RemovePeriodsAtEndsOfUsernames < ActiveRecord::Migration
+class RemovePeriodsAtEndsOfUsernames < ActiveRecord::Migration[4.2]
   include Gitlab::ShellAdapter
 
   class Namespace < ActiveRecord::Base

db/migrate/20150423033240_add_default_project_visibililty_to_application_settings.rb

-class AddDefaultProjectVisibililtyToApplicationSettings < ActiveRecord::Migration
+class AddDefaultProjectVisibililtyToApplicationSettings < ActiveRecord::Migration[4.2]
   def up
     add_column :application_settings, :default_project_visibility, :integer
     visibility = Settings.gitlab.default_projects_features['visibility_level']

db/migrate/20150425164646_gitlab_change_collation_for_tag_names.acts_as_taggable_on_engine.rb

 # This migration is a duplicate of 20150425164651_change_collation_for_tag_names.acts_as_taggable_on_engine.rb
 # It shold be applied before the index additions to ensure that `name` is case sensitive.
 
-class GitlabChangeCollationForTagNames < ActiveRecord::Migration
+class GitlabChangeCollationForTagNames < ActiveRecord::Migration[4.2]
   def up
     if ActsAsTaggableOn::Utils.using_mysql?
       execute("ALTER TABLE tags MODIFY name varchar(255) CHARACTER SET utf8 COLLATE utf8_bin;")

db/migrate/20150425164647_remove_duplicate_tags.rb

 # rubocop:disable all
-class RemoveDuplicateTags < ActiveRecord::Migration
+class RemoveDuplicateTags < ActiveRecord::Migration[4.2]
   def up
     select_all("SELECT name, COUNT(id) as cnt FROM tags GROUP BY name HAVING COUNT(id) > 1").each do |tag|
       tag_name = quote_string(tag["name"])

db/migrate/20150425164648_add_missing_unique_indices.acts_as_taggable_on_engine.rb

 # rubocop:disable all
 # This migration comes from acts_as_taggable_on_engine (originally 2)
-class AddMissingUniqueIndices < ActiveRecord::Migration
+class AddMissingUniqueIndices < ActiveRecord::Migration[4.2]
   def self.up
     add_index :tags, :name, unique: true
 

db/migrate/20150425164649_add_taggings_counter_cache_to_tags.acts_as_taggable_on_engine.rb

 # rubocop:disable all
 # This migration comes from acts_as_taggable_on_engine (originally 3)
-class AddTaggingsCounterCacheToTags < ActiveRecord::Migration
+class AddTaggingsCounterCacheToTags < ActiveRecord::Migration[4.2]
   def self.up
     add_column :tags, :taggings_count, :integer, default: 0
 

db/migrate/20150425164650_add_missing_taggable_index.acts_as_taggable_on_engine.rb

 # This migration comes from acts_as_taggable_on_engine (originally 4)
-class AddMissingTaggableIndex < ActiveRecord::Migration
+class AddMissingTaggableIndex < ActiveRecord::Migration[4.2]
   def self.up