ZF Training Authentication

<?php

class AuthController extends Zend_Controller_Action
{

    public function init()
    {
        $db = Zend_Db::factory('Pdo_Mysql', array(
            'host'     => 'localhost',
            'username' => 'test',
            'password' => 'test',
            'dbname'   => 'test',
        ));
        Zend_Db_Table::setDefaultAdapter($db);
    }

    public function indexAction()
    {
        // action body
    }

    public function loginAction()
    {
        $config  = $this->getInvokeArg('bootstrap')->getOption('auth');
        $salt    = $config['salt'];
        $auth = new Zend_Auth_Adapter_DbTable(
            Zend_Db_Table::getDefaultAdapter(),
            'users',
            'email',
            'password',
            'SHA1(?)'
        );
        $auth->setIdentity($this->getRequest()->getPost('email'))
             ->setCredential($this->getRequest()->getPost('password') . $salt);
        $result = $auth->authenticate();
        echo $result->isValid();
    }


}