public ActionResult Create(RoadTrip roadtrip)
        {
            if (ModelState.IsValid)
            {
                db.RoadTrips.Add(roadtrip);
                db.SaveChanges();
                return RedirectToAction("Index");
            }

            return View(roadtrip);
        }
 public ActionResult Edit(RoadTrip roadtrip)
 {
     if (ModelState.IsValid)
     {
         db.Entry(roadtrip).State = EntityState.Modified;
         db.SaveChanges();
         return RedirectToAction("Index");
     }
     return View(roadtrip);
 }