function registerDevice() {
      var push = new $window.Ionic.Push({
        onNotification: function() {
          $window.alert('새 댓글이 달렸습니다.');
        }
      });
      var deferred = $q.defer();
      push.register(function(data) {
        deferred.resolve(data._token);
      });
      return deferred.promise;
    }


        function login() {
      $ionicLoading.show();
      registerDevice()
        .then(function(token) {
          LoginModel.form.deviceToken = token;
          return Users.register({}, LoginModel.form).$promise;
        })
        .then(function() {
          return Users.login({}, {
            identifier: LoginModel.form.username,
            password: LoginModel.form.password
          }).$promise;
        })
        .then(function(authData) {
          appStorage.token = authData.token;
          appStorage.user = authData.user;
          $ionicLoading.hide();
          $state.go('postList');
        })
        .catch(function(err) {
          console.log(err);
          $ionicLoading.hide();
          $ionicPopup.alert({
            title: '로그인 실패',
            template: '다른 아이디로 로그인 해주세요'
          });
        });
    }