action_plan.rb

# app/models
class User < ActiveRecord::Base
  has_many :responses, dependent: :destroy
end

class Response < ActiveRecord::Base
  has_one :report
  has_many :points
  belongs_to :user
end

class Report < ActiveRecord::Base
  belongs_to :response
end

class Point < ActiveRecord::Base
  belongs_to :response
end

# config/routes.rb
resources :users do
  resources :responses do
    resources :action_plans
  end
end

# app/controllers/action_plans_controller.rb
class ActionPlansController < ApplicationController
  before_filter :response

  def new
    @report = @response.build_report
    5.times do
      @response.points.build
    end
  end

private
  def response
    @response = current_user.responses.find(params[:id])
  end
end

# http://localhost:3000/users/{:user_id}/responses/{:id}/action_plans/new
# Throws undefined method `committed?' for Response Object