add first version of domain model

docs/diagrams/domain_model_frag_jetzt.puml

+@startuml
+
+skinparam class {
+	BackgroundColor PaleGreen
+	BorderColor Green
+	ArrowColor black
+	FontSize 28
+	BackgroundColor<<USP>> Pink
+	BorderColor<<USP>> HotPink
+}
+
+skinparam backgroundColor Linen
+skinparam linetype ortho
+skinparam shadowing true
+skinparam minClassWidth 200
+skinparam LegendBackgroundColor Strategy
+skinparam LegendBorderThickness 0
+skinparam LegendFontSize 20
+skinparam defaultFontSize 20
+skinparam Padding 8
+skinparam Nodesep 150
+skinparam ArrowThickness 2
+skinparam ArrowColor DarkSlateGray
+
+hide methods
+hide empty members
+hide circle
+
+package "frag.jetzt | domain diagram" <<Frame>> {
+
+class Role {
+}
+
+class GuestUser {
+}
+
+class RegisteredUser {
+  email
+  password
+}
+
+GuestUser -left-|> Role
+RegisteredUser -up-|> Role
+
+class SessionParticipant {
+}
+
+class TemporalSessionOwner {
+}
+
+SessionParticipant -left-|> GuestUser
+TemporalSessionOwner -up-|> GuestUser
+
+class Moderator <<USP>> {
+}
+
+class BonusParticipant <<USP>> {
+}
+
+class PermanentSessionOwner {
+}
+
+PermanentSessionOwner -left-|> RegisteredUser
+Moderator -up-|> RegisteredUser
+Moderator -down- Session :assigned to >
+BonusParticipant -right-|> RegisteredUser
+
+class Session {
+  id
+  name
+  description
+  owner
+  }
+
+class Question {
+  votes
+}
+
+class Status {
+  affirmed
+  negated
+  bonus
+  discussed
+}
+
+Status -up- Question
+
+class Board {
+  help
+}
+
+class QuestionBoard {
+  counter
+  search
+  sorting
+  filtering
+  displayThreshold
+}
+
+class ModeratorBoard {
+  counter
+  search
+  sorting
+  filtering
+}
+
+Session *-right- Board
+QuestionBoard -up-|> Board
+ModeratorBoard -up-|> Board
+Question -right-o QuestionBoard
+ModeratorBoard o-down- BannedQuestion
+
+class Configuration {
+  theme
+  language
+}
+
+}
+
+legend right
+  |=<img:https://git.thm.de/arsnova/frag.jetzt/raw/master/src/assets/icons/mstile-150x150.png> |= \n [[https://frag.jetzt frag.jetzt]] \n\n\n THM\n Technische Hochschule Mittelhessen \n University of Applied Sciences \n Department of Computer Sciences |
+  | Projekt-Website | [[https://frag.jetzt]] |
+  | «USP» | Alleinstellungsmerkmale von frag.jetzt |
+  | Repository | [[https://git.thm.de/arsnova/frag.jetzt]] |
+  | Staging Server | [[https://staging.frag.jetzt]] |
+  | UML-Tool| PlantUML v1.2019.5|
+  | Modellversion| 1.0 |
+  | Erstelldatum| 25.08.2019 |
+  | Ersteller| Klaus Quibeldey-Cirkel|
+  | Mail| klaus.quibeldey-cirkel@mni.thm.de |
+  | Letzte Änderung| 26.08.2019 |
+end legend
+
+@enduml