public async Task<JsonResult> Exchangers(Guid give, Guid get, double amount = 1, bool? calculateGive = null)
 {
     using (var service = new ExchangersService())
     {
         var res = await service.GetExchangersByPaymentsAsync(give, get, amount, calculateGive);
         return new JsonResult()
         {
             Data = res,
             JsonRequestBehavior = JsonRequestBehavior.AllowGet
         };
     }
 }
 public async Task<JsonResult> PaymentSystems()
 {
     using (var service = new ExchangersService())
     {
         var res = await service.GetPaymentSystemsAsync();
         return new JsonResult()
         {
             Data = res,
             JsonRequestBehavior = JsonRequestBehavior.AllowGet
         };
     }
 }