public JsonResult ActivateCoupons(int couponId, int amount)
        {
            var user     = _userService.GetUserByEmail(User.Identity.Name);
            var response = _couponService.ActivateCoupons(couponId, amount, user.Id);

            return(new JsonResult
            {
                ContentType = "application/json",
                Data = response
            });
        }