public ActionResult AddChallenge(Challenge challenge)
        {

            RavenService.SaveChallenge(RavenSession, challenge);

            return RedirectToAction("AddChallenge");
        }
 public ActionResult AddChallenge()
 {
     var model = new Challenge();
     return View(model);
 }
        public static void SaveChallenge(IDocumentSession session, Challenge challenge) {
           
           session.Store(challenge);
           session.SaveChanges();

        }