Fixes #19541 - properly mark user <-> mail_notification relation
Mark `:inverse_of` on `User` and `UserMailNotification` objects so the relation properties would be set automatically, even for new in-memory instances.
Related issues
Bug #19541: UserMailNotification records are not set up properly when a mail notification is added.
Added by Shimon Shtein almost 7 years ago
Fixes #19541 - properly mark user <-> mail_notification relation
Mark `:inverse_of` on `User` and `UserMailNotification` objects
so the relation properties would be set automatically, even for
new in-memory instances.