public function unlock()
    {
        $userid = $this->getObject('user')->getId();

        //Only an saved row can be unlocked by the user who locked it
        if(!$this->isNew() && $this->locked_by != 0 && $this->locked_by == $userid)
        {
            $this->locked_by = 0;
            $this->locked_on = 0;

            $this->save();
        }

        return true;
    }