class Product < ActiveRecord::Base
	set_primary_keys :id  # redundant
	has_many :product_tariffs, :foreign_key => :product_id
	has_one :product_tariff, :foreign_key => :product_id

	has_many :tariffs, :through => :product_tariffs, :foreign_key => [:tariff_id, :tariff_start_date]
end