public ActionResult Add(TravelOrder t)
 {
     if (ModelState.IsValid)
     {
         repo.AddTravelOrder(t);
         return(RedirectToAction("All"));
     }
     else
     {
         ViewBag.types   = repo.GetTravelOrderTypes();
         ViewBag.drivers = repo.GetDrivers();
         ViewBag.cities  = repo.GetCities();
         ViewBag.car     = repo.GetCars();
         return(View(t));
     }
 }