public async Task <IActionResult> PostOrderItem([FromBody] OrderItemChangeDto itemDto)
        {
            try
            {
                var item = _mapper.Map <OrderItem>(itemDto);

                var order = await _repository.AddOrderItem(item);

                await _repository.Save();

                return(CreatedAtAction("GetOrder",
                                       new { controller = "orders", id = item.OrderId },
                                       _mapper.Map <OrderDto>(order)));
            }
            catch (DbUpdateException e)
            {
                ModelState.AddModelError("database", e.InnerException != null
                    ? e.InnerException.Message
                    : e.Message);
                return(ValidationProblem());
            }
            catch (Exception e)
            {
                return(_helpers.ErrorResponse(e));
            }
        }