CakePHP ARO rebuild shell task

RebuildAroShell.php

<?php
class RebuildAroShell extends AppShell {

    public $uses = array('User', 'Group');

    public function main() {
        $groups = $this->Group->find('all');
        $users = $this->User->find('all');

        $aro = new Aro();

        foreach ($groups as $group) {
            $aro->create();
            $aro->save(array(
                'foreign_key' => $group['Group']['id'],
                'model' => 'Group',
                'parent_id' => null
            ));
        }

        $aros = array();

        // Index
        $i = 0;

        foreach ($users as $user) {
            $aros[$i++] = array(
                'foreign_key' => $user['User']['id'],
                'model' => 'User',
                'parent_id' => $user['User']['group_id']
            );
        }

        foreach ($aros as $data) {
            $aro->create();
            $aro->save($data);
        }
    }

}