Accessrules And Action + Switch

Hello. I have action - actionCity with switch (add, delete, update) for link example: site.com/admin/city/add

Code:

<?php
class AdminController extends Controller
{
public function filters()
{
	return array(
		'accessControl', // perform access control for CRUD operations
		'postOnly + delete', // we only allow deletion via POST request
	);
}
public function accessRules()
{
	return array(
		array('allow',
			'actions'=>array('city'),
			'users'=>array('admin');
		),
		array('deny',  // deny all users
			'users'=>array('*'),
		),
	);
}

public function actionCity($id=null, $act=null)
{
	switch($act)
	{
			case 'add':
				$city = new City;
				if (isset($_POST['City']))
				{
					$city->attributes = $_POST['City'];
					if($city->save())
						$this->redirect('/admin/city/');
				}
				
				$this->render('city/create', array(
					'city' => new City,
				));
			break;
	}

}

}

I don't know correctly this code or not, but it's work.

And my question: How I can do accessrules for add,delete,update?
Thanks.