Illuminate\Database\Eloquent\Builder::addUpdatedAtColumn PHP 메소드

    protected function addUpdatedAtColumn(array $values)
    {
        if (!$this->model->usesTimestamps()) {
            return $values;
        }
        $column = $this->model->getUpdatedAtColumn();
        return Arr::add($values, $column, $this->model->freshTimestampString());
    }