My app has Groups, and Groups have an Admin, Notables (people with additional permissions), and Members (people with standard permissions). I need help with modeling these, as I have lot's of ideas but don't really know where to start, e.g. do I use a Memberships model? If so, where would Notables and Admins fit in? Do I also need a permissions model which handles the rights of Notables and Admins, too?
How would you model the relationships for this?