public HttpResponseMessage Remove(CartItemViewModel item)
 {
     var userId = User.Identity.GetUserId();
     // remove items from db
     return Request.CreateResponse(HttpStatusCode.OK);
 }
 public HttpResponseMessage Add(CartItemViewModel item)
 {
     var userId = User.Identity.GetUserId();
     // store in db tied to userId
     return Request.CreateResponse(HttpStatusCode.OK);
 }