public function setLastRunUser($user = null)
    {
        if (is_null($user)) {
            $user = Mage::helper('aoe_scheduler')->getRunningUser();
        }

        // Log the current user running the schedule if it's executed
        Mage::getModel('core/variable')
            ->loadByCode(Aoe_Scheduler_Helper_Data::VAR_LAST_RUN_USER_CODE)
            ->setCode(Aoe_Scheduler_Helper_Data::VAR_LAST_RUN_USER_CODE)
            ->setName('Scheduler - User Last Run As')
            ->setPlainValue((string) $user)
            ->save();

        return $this;
    }