Zend_Acl

<?php
class Application_Model_Acl extends Zend_Acl
{
    public function __construct()
    {
        $this->addRole('reader');
        $this->addRole('editor', 'reader');
        $this->addRole('copywriter', 'editor');

        $this->addResource('stories');
        $this->addResource('edit-stories');
        $this->addResource('publish-stories');

        $this->allow('reader', 'stories', 'read');
        $this->allow('editor', 'edit-stories', array ('create','update'));
        $this->allow('copywriter', 'publish-stories', array ('publish'));
    }
}