* Add missing copyright note to AnonymousUser [ci skip]
* Addin PlaceholderUser model and its associations
* Ensure PlaceholderUser do not "leak out" uncontrolled
* Extract Associations for User and PlaceholderUser.
- remove obsolete #assigned_issues
- remove obsoete #:responsible_for_issues
- add specs and factory for PlaceholderUser
Adding specs to PlaceholderModel
* Migration: enforce uniqueness of lastname for Group and PlaceholderUser
* Remove obsolete callback `after_add` on groups association.
The association of principals and groups still had a callback
`after_add` that called a method `user_added` on the group.
That method was not defined anymore as it was removed in
commit d93ff52a27.
* Move validation for #groupname to the right spec.
* Cleanup placeholder and group specs
* Remove Setting `workpackage_group_assignment`
* Refactoring: Extract assignable scope from Project to Member
* Refactor: Add Member scope not_locked.
* deprecate hacky scope
* remove wp_group_assignment specific test case
Co-authored-by: ulferts <jens.ulferts@googlemail.com>
Alexander Brandon Coles