Login after successful signup Ember-Simple-Auth

1

I have set up a auto-authenticate for user after signup:

app/libs/auto-authenticate.js

export default Ember.SimpleAuth.Authenticators.OAuth2.extend({                  
authenticate: function(credentials) {                                                        
 if(!Ember.isEmpty(credentials.access_token)) {                               
   return Ember.RSVP.resolve(credentials);                                                  
  } else {                                                                                   
    return this._super(credentials);                                                         
  }                                                                                          
 }                                                                                            
});

app/app.js

import AutoAuthenticate from 'appkit/libs/auto-authenticate';
App.initializer({                                                                              
  name: 'auto',                                                                                
  initialize: function(container, application) {                                               
    container.register('app:authenticators:custom',   AutoAuthenticator);         
    Ember.SimpleAuth.setup(container, application);                                            
  }                                                                             
});

app/controllers/register.js

export default Ember.ObjectController.extend({
firstname: '',                                                                
lastname: '',                                                                                
username: '',                                                                                
password: '',                                                                                                                                                                             
actions: {                                                                                   
  registerUser: function(){                                                                  
    var self = this;                                                                         
    var user = this.store.createRecord('user', {                                             
      first_name: this.get('firstname'),                                       
      last_name: this.get('lastname'),                                                       
      username: this.get('username')                                                         
    });
    user.set('typedPass', this.get('password'));                                             
    user.save().then(function(){                                                             
      //How can I login this user using ember-simple-auth ?? 
    });                                                                       
  }                                                                                          
}                                                                                            
});

I have separate Login for users that will provide their username and password.

What I want to do is , when a new user signs up in the website I want that user to logged in directly without going to the login page and providing its username/password ? As I am getting the username and password from the registration process, I dont want the user to go to another route and then login . How to call the custom authenticator to authenticate the current signed up user with its login credentials?? Stackoverflow Question