Different columns for group table

[ECode16]

Table for groups has user_id, name of group and created_at timestamp. I want to remove the created_at column and add one that would store id of admin who added user to the group.

I extended GroupModel and changed $allowedFields but the old Model is hardcoded in private function of Authorizable trait (saveGroups and populateGroups plus group creation in saveGroupsOrPermissions) which are used by the whole file.

I tried to create my own trait to override the original one, but got its declaration was incompatible the original ones due to return type self.

Copying the edited trait into my User Entity worked but is there better way to do it?