can't show logout button after $createUser - angularjs

Question

I'm following thinkster's ang-news tutorial to build authentication using firebase. I can create users with a service and controller but after registering a new user they are not logged in.
I have a auth.js service:
app.factory('Auth', ['$rootScope', 'FIREBASE_URL', '$firebaseSimpleLogin', function($rootScope, FIREBASE_URL, $firebaseSimpleLogin){
var ref = new Firebase(FIREBASE_URL);
var auth = $firebaseSimpleLogin(ref);
var Auth = {
register: function(user){
return auth.$createUser(user.email, user.password);
},
signedIn: function(){
return auth.user !== null; // user signed in if user property is not null
},
login: function(user){
return auth.$login('password', user); // type of login
},
logout: function(){
auth.$logout();
}
};
$rootScope.signedIn = function(){
return Auth.signedIn();
};
return Auth;
}]);
auth.user always stays null.
This is my controller:
app.controller('AuthCtrl', ['$scope', '$location', 'Auth', function($scope, $location, Auth){
if (Auth.signedIn()){
$location.path('/')
}
$scope.register = function(){
Auth.register($scope.user).then(function(authUser){
console.log('authUser: ' + JSON.stringify(authUser))
$location.path('/');
})
}
}])
Then I have a register.html with an email/password form. It calls register():
<form ng-submit='register()' novalidate>
<input type='email' placeholder='Email' class='form-control' ng-model='user.email'>
<input type='password' placeholder='Password' class='form-control' ng-model='user.password'>
<input type='submit' class='btn btn-success' value='Register'>
</form>
The users get generated in my Firebase Forge, but after I submit the register form, the Logout button does not show:
<ul class='nav navbar-nav navbar-right' ng-show='signedIn()'>
<li>
<a href='#' ng-click='logout()'>Logout</a>
</li>
</ul>
Why does signedIn() stay falsey after I create a user in the firebase forge?

Answer 1

Creating a user does not automatically log them in (though it used to in an older version of angularFire).
Change your controller method to look like:
$scope.register = function(){
Auth.register($scope.user).then(function(authUser){
console.log('authUser: ' + JSON.stringify(authUser))
Auth.login($scope.user);
$location.path('/');
})
}
This will create the user in the Forge and then once that promise resolves, it will automatically log them in.