public object Add(string name)
 {
     var user = new User
         {
             Name = name,
         };
     Session.Store(user);
     return Json(user.Id);
 }
 public void Save2(int id, User user, Guid etag)
 {
     Session.Advanced.UseOptimisticConcurrency = true;
      Session.Store(user, etag, "users/" + id);
 }