Take advantage of the Model inheritance provided by polymodel.PolyModel to have create a class hierarchy rooted at Person. Also, add some missing Role classes, such as Role, (Organization) Mentor, (Club) Member, (School) Student. Make (Organization) Administrator be a Reviewer like Mentor is. Patch by: Todd Larsen Review by: Pawel Solyga, Sverre Rabbelier, Augie Fackler Review URL: http://codereviews.googleopensourceprograms.com/607