Using Active Support Concerns

noteable.rb

require 'activesupport/concern'

module Noteable
  extend ActiveSupport::Concern
  
  included do
   has_many :notes, as: :noteable
  end
  
  def note_taking_action
    # do stuff here
  end
  
  ...
  
end

product.rb

class Product < ActiveRecord::Base
  include Noteable
  
  ...
    
end