gistfile1.rb

class Profile < ActiveRecord::Base 
  has_many                  :profiles_users, :class_name => "ProfilesUsers"
  has_many                  :users, :through => :profiles_users
  has_many                  :admins, 
                            :through => :profiles_users,
                            :source => :user,
                            :conditions => ["profiles_users.role = ?", "admin"]
  has_many                  :editors, 
                            :through => :profiles_users,
                            :source => :user,
                            :conditions => ["profiles_users.role = ?", "editor"]
...

# would like to be able to do something like this:
@profile.create params[:profile]
@profile.admins << current_user
@profile.editors << another_user

# instead the role field is being left blank 

# ideally would also like to be able to do:
@profile.owner = current_user