1.6.6. Use IHttpActionResult

• Modify controller, replace rurn type from CustomerDto to IHttpActionResult

        // GET /api/customers/1
        public IHttpActionResult GetCustomers(int id)
        {
            var customer = _context.Customers.SingleOrDefault(c => c.Id == id);

            if (customer == null)
            {
                return NotFound();
            }

            return Ok(Mapper.Map<Customer, CustomerDto>(customer));
        }

        // POST /api/customers
        [HttpPost]
        public IHttpActionResult CreateCustomers(CustomerDto customerDto)
        {
            if (!ModelState.IsValid)
            {
                return BadRequest();
            }
            var customer = Mapper.Map<CustomerDto, Customer>(customerDto);
            _context.Customers.Add(customer);
            _context.SaveChanges();
            customerDto.Id = customer.Id;

            return Created(new Uri(Request.RequestUri + "/" + customer.Id), customer);
        }