public ActionResult Index(string _signedRequest)
        {
            dynamic response = GetFacebookUserData(_signedRequest);
            if (response == null)
                return new RedirectResult("/");

            Contact contact = new Contact();
            contact.FirstName = response.first_name;
            contact.LastName = response.last_name;
            contact.DateOfBirth = DateTime.Parse(response.birthday);
            contact.Email = response.email;

            StateData stateData = new StateData();
            stateData.FBSignedRequest = _signedRequest;
            stateData.FBUserId = response.id;

            ContactInfoViewModel model = new ContactInfoViewModel();
            model.contact = contact;
            model.state = stateData;

            if (contactRepository.IsRegistered(response.id))
                return RedirectToAction("RegisterComplete");
            else
                return View(model);
        }
        public ActionResult Index(ContactInfoViewModel _model)
        {
            if (_model.state.FBSignedRequest == null)
                return new RedirectResult("/");

            dynamic response = GetFacebookUserData(_model.state.FBSignedRequest);

            _model.contact.PartitionKey = response.id;

            if (contactRepository.IsRegistered(response.id))
                return RedirectToAction("RegisterComplete");

            if (ModelState.IsValid)
            {
                //save
                contactRepository.Save(_model.contact);

                //redirect to selectstore action

                return RedirectToAction("SelectStore", new { _fbsignedRequest = _model.state.FBSignedRequest, _fbuserid = _model.state.FBUserId});
            }

            return View(_model);
        }