title: Firebase.set failed: second argument must be a valid function
body: <p>Following Lynda.com Building a data-driven app with angular and Firebase.
  I am getting the above message when I attempt to use the register function with set(). set() is still in the angularfire API. I have tried searching SO and the docs but cannot find the answer.</p>
  
  <p>authentication.js</p>
  
  <pre><code>myApp.factory('Authentication', function($firebase, 
    $firebaseAuth, $routeParams, $location, FIREBASE_URL) {
  
    var ref = new Firebase(FIREBASE_URL);
    var auth = $firebaseAuth(ref);
  
    //Temporary object
    var myObject = {
  
      login: function(user) {
        return auth.$authWithPassword({
          email: user.email,
          password: user.password
        }); //authWithPassword
      }, //login
  
      register: function(user) {
        return auth.$createUser({
          email: user.email,
          password: user.password
        }).then(function(regUser) {
          var firebaseUsers = new Firebase(FIREBASE_URL+'users');
  
          var userInfo = {
            date : Firebase.ServerValue.TIMESTAMP,
            regUser : regUser.uid,
            firstname: user.firstname,
            lastname : user.lastname,
            email: user.email
          }; //user info
  
          firebaseUsers.set(regUser.uid, userInfo); //**ERRORS HERE**
        }); //promise
      } //register
  
    }; //myObject
    return myObject;
  }); //myApp Factory
  </code></pre>