making check box remember me working by saving the username & password

I am making a web app using yii and yiibooster extension. I have a login page with a login id and a password. there is also a chaeck box available there, the propose is to save the username + password if the check box is checked, and not if its not checked.

this is my userIdentity.php this is my loginform.php here is my siteController.php and login.php

I am new to yii and I need some help. I followed this tutorial to be able to make the checkbox work, it didnt. can someone help please? thanks.