module Model
  module MongoDb
    module Customizable
      extend ActiveSupport::Concern 
      
      included do
        # cache association as a shortcut
        belongs_to :product
        
        # for cases like f.object.send(association).klass.new in link_to_add_fields(name, f, association, options = {})
        after_initialize :cache_product_association
        
        before_validation :cache_product_association
        
        private
      
        def cache_product_association
          raise NotImplementedError
        end
      end
    end
  end
end