I’ve removed everything related to the feature based on this commit:
ce08f919f34fd8849834365

Resolves #10857.

Fix underscore template error.
Fix `=` spacing

Improve and finish the fallback to the In-Reply-To and References header for the reply-by-email feature

A few things to note:
- The IncomingEmail feature is now enabled even without a
  correctly-formatted sub-address
- Message-ID for new thread mail are kept the same so that subsequent
  notifications to this thread are grouped in the thread by the email
  service that receives the notification
  (i.e. In-Reply-To of the answer == Message-ID of the first thread message)
- To maximize our chance to be able to retrieve the reply key, we look
  for it in the In-Reply-To header and the References header
- The pattern for the fallback reply message id is "reply-[key]@[gitlab_host]"
- Improve docs thanks to Axil

# Conflicts:
#	Gemfile.lock

They would try to load JSON from a project even though it isn't a single project

When a build status changes a notification will popup.
Fixes #10851

1. Allow subscribing (the current user) to a label

- Refactor the `Subscription` coffeescript class
  - The main change is that it accepts a container, and conducts all
    DOM queries within its scope. We need this because the labels
    page has multiple instances of `Subscription` on the same page.

2. Creating an issue or MR with labels notifies users subscribed to those labels

- Label `has_many` subscribers through subscriptions.

3. Adding a label to an issue or MR notifies users subscribed to those labels

- This only applies to subscribers of the label that has just been
  added, not all labels for the issue.

Previously we were doing all of kinds of code gymnastics and flash abuse
in order to work with a Doorkeeper controller but have it _appear_ at
the `/profile/applications` path. Fortunately we can just tell Rails to
use a different controller to handle that route, and we get the best of
both worlds.

This reverts commit 5a586f36

This reverts merge request !3191

Closes #13805

This code is mostly a copy-paste from existing pull requests so there's
no point in running Rubocop on it.

This ensures that options such as `using: :gin` and PostgreSQL operator
classes are ignored when loading a schema into a MySQL database.

This is needed to support creating/dumping/loading indexes that use the
gin_trgm_ops operator class on PostgreSQL. These changes are taken from
Rails pull request https://github.com/rails/rails/pull/19090.

Signed-off-by: Dmitriy Zaporozhets <dmitriy.zaporozhets@gmail.com>

Prevent Groups to have smaller visibility than projects
Add default_group_visibility_level to configuration
Code improvements

Signed-off-by: Dmitriy Zaporozhets <dmitriy.zaporozhets@gmail.com>

Closes https://gitlab.com/gitlab-org/gitlab-ce/issues/12944

* Add Labels tab to Groups
* Add decorator for label so it's aware of Milestones.

in order to have it the same way like in omnibus

Fixes #3768

Fixes #12731

The only major difference with the EE version is the change from a light and dark logo to only a header logo
The dark logo wasn't used anyway, so it seemed to make sense to me to rename the field to the actual function of it