Rails 3 has_many :through + join table conditions / scoping

Question

I\'m working on an app that has the models User and Project, and User can be assigned to multiple Projects, via Project

Answer 1

It sounds like what you're looking for is a combination of RoR's single table inheritance and named scopes.

Take a look at the following article for a nice example about polymorphic associations. This should help you with achieving the following:

@project.developers
  # returns @project.users, but only where ProjectUser.role = 'Developer'

@project.designers << @user
  # creates a ProjectUser for @project, @user with role 'Designer'

Scopes will give you a clean way to implement @user.development_projects but there may be more trickery required to get the << operator.