public ActionResult Edit(Dinner dinner)
        {
            if (!dinner.IsHostedBy(User.Identity.Name))
            {
                return View("InvalidOwner");
            }

            if (ModelState.IsValid)
            {
                db.Entry(dinner).State = EntityState.Modified;
                db.SaveChanges();
                return RedirectToAction("Index");
            }
            return View(dinner);
        }