public HttpResponseMessage AddProduct(Product product)
        {
            var prod = appSrv.GetAllProducts(x => x.ProductID == product.ProductID)
                       .SingleOrDefault();

            if (prod != null)
            {
                prod.ProductName = product.ProductName;
                prod.CategoryID  = product.CategoryID;
            }

            var result = appSrv.AddProduct(prod ?? product);

            if (result > 0)
            {
                return(Request.CreateResponse(HttpStatusCode.OK));
            }

            return(Request.CreateResponse(HttpStatusCode.ExpectationFailed));
        }