Model association that spans across parent app and engine

Question

I'm making a Rails engine that makes reference to the current_user in a controller like so:

require_dependency "lesson_notes/application_controller"

module LessonNotes
  class NotesController < ApplicationController

    def index
      if current_user
        @notes = Note.where(student: current_user) if current_user.user_type.name == "student"
        @notes = Note.where(teacher: current_user) if current_user.user_type.name == "teacher"
      end
    end

  end
end

This is quite verbose and it would seem I could do something like this instead:

require_dependency "lesson_notes/application_controller"

module LessonNotes
  class NotesController < ApplicationController

    def index
      @notes = current_user.notes if current_user
    end

  end
end

However, the user model exists in the parent app, not the engine.

In the Note model I have this to define the belongs_to association:

module LessonNotes
  class Note < ActiveRecord::Base
    belongs_to :student, class_name: "::User"
    belongs_to :teacher, class_name: "::User"
  end
end

How would I define the other side of the association - the has_many - in the User model?

Answer 1

This is how I ended up doing it...

In the parent app:

class User < ActiveRecord::Base

  has_many   :notes, class_name: LessonNotes::Engine::Note, foreign_key: "teacher_id"

end