public IActionResult Get()
        {
            var receipt = new Receipt();

            receipt.AddCustomerNumber("123");
            receipt.AddItem(new Item("Milk", new Amount(CurrencyEnum.EUR, 10.0f)));
            receipt.AddItem(new Item("Egs", new Amount(CurrencyEnum.EUR, 5.0f)));
            receipt.AddItem(new Item("Honey", new Amount(CurrencyEnum.EUR, 2.0f)));

            return(Ok(receipt.ToJson()));
        }