* Prepare factories and associations for Users::DeleteActivity specs
* Altered user associations, delete the needed associations in Users::DeleteActivity
* Moved and refined user deletion spec
* Removed useless commented user associations
* Refactored BackupData factory
* Refactored ProfilePin factory
* Refactored Reaction factory
* Fixed specs: Keep default _type in factories or specify it in tests
* Ok, notes shouldn't be deleted on user deletion
* Fixed creating reactable for specs
* Specify commentable/commentable_type explicitly when creating data for tests
* Fixed typo in the comments spec
* Removed unnneeded space
* Added aggregate_failures for testing user associations deletion
* Keep feedback_messages while deleting user activities
* Add new columns to notifications table
* Remove stream from notifications and add new methods
* Turn off moderation comment notifications
* Add notifiable_type index to migration
* Stop creation of Stream-based notification model instances
* Add notification model create hooks
* Add badge achievement notification creation hook
* Fix some specs
* Add missing @ symbol
* Fix for tests and rename a few things
* forgot to uncomment code sigh
