def coupons= coupons
      self.coupon_codes = coupons.map do |coupon|
        coupon.coupon_code if coupon.respond_to? :coupon_code
      end.compact
      attributes[:coupons] = coupons
    end
def coupons= coupons
      self.coupon_codes = coupons.map do |coupon|
        coupon.coupon_code if coupon.respond_to? :coupon_code
      end.compact
      attributes[:coupons] = coupons
    end
Assign Coupon resources (rather than coupon codes).

 @param coupons [[Coupons]]