public async Task <Object> Post(dynamic model)
        {
            InvoiceModel c = JsonConvert.DeserializeObject <InvoiceModel>(model.ToString());

            InvoiceModel reciept = _invoiceServices.Calculate(c);

            invoices.Add(reciept);

            List <InvoiceModel> list = invoices;

            using (StreamWriter writer = new StreamWriter($"{reciept.Id}_invoice.txt"))
            {
                writer.WriteLine($"\t INVOICE #{reciept.Id} ");
                writer.WriteLine();
                writer.WriteLine($"Bonus Point = {reciept.BonusPoints}. ");
                writer.WriteLine();
                writer.WriteLine($@"\t---------Products Rented---------");
                writer.WriteLine();
                foreach (InventoryModel product in reciept.Inventories)
                {
                    writer.WriteLine($@"{product.Name}          {product.RentDays} days             ${product.Cost}.00 ");
                }

                writer.WriteLine();
                writer.WriteLine();
                writer.WriteLine($"\t Total \t : \t${reciept.TotalPrice}.00");
            }

            return(new
            {
                reciept.Id,
                reciept.BonusPoints,
                reciept.TotalPrice,
                reciept.PurchaseDate,
                reciept.UserId,
                reciept.Inventories
            });
        }