polymorphic and one-to-many association

Question

I have a Collaboration model with a polymorphic association with a Grade | School, and a one-to-many association with a User

  belongs_to :owner, polymorphic: true
  belongs_to :user, foreign_key: "teacher_id"

this is the way i manage the users who can access a school or a grade. Now, what i need is to do something like this

School.first.teachers 
Grade.first.teachers

I think it would be something like this in the Grade/School model

has_many :teachers, through: :collaborations, foreign_key: "teacher_id" 

but it doesn't seem to be the right solution. Any ideas?

Answer 1

has_many :collaborations, :as => :owner
has_many :teachers, :through => :collaborations, :source => :user

Answer 2

You need to establish the polymorphic association to collaborations. Try:

class School < ActiveRecord::Base
  has_many :collaborations, :as => :owner
  has_many :teachers, :through => :collaborations
end