override - Show customer groups in my account smarty template prestashop 1.6 -

i want show customer groups in account smarty template.that why need add smarty variable template. wanted override frontcontroller.php , use function available in think doing wrong code in prestashop 1.6.

public function init() {     parent::init();     self::$smarty->assign('customergroups', parent::getcurrentcustomergroups()); }