public HttpResponseMessage PostOrder(
            int customerKey, OrderRequestModel requestModel,
            HttpRequestMessage request)
        {
            var order = requestModel.ToOrder(customerKey);

            _orderRepository.Add(order);
            _orderRepository.Save();

            var response = request.CreateResponse(HttpStatusCode.Created, order);

            response.Headers.Location = new Uri(
                Url.Link(
                    "CustomerOrdersHttpRoute",
                    new { customerKey = customerKey, key = order.Key }
                    )
                );

            return(response);
        }