public function orWhereIn($key, $value, $operator = 'IN')
    {
        $exp = explode(',', $value);
        $this->where[] = 'OR OR'.$key.' '.$operator.' ('.$this->createPlaceHolder($exp).') ';

        foreach ($exp as $key => $val) {
            $this->bindings[$key] = $val;
        }

        return $this;
    }