public function migrate()
    {
        // find migrations
        $folders = $this->app->pathfinder->search('dbupdates', '', 'path');
        // todo - sort files in folders
        foreach ($folders as $dir) {
            $files = scandir($dir);
            sort($files);
            foreach ($files as $name) {
                if (strtolower(substr($name, -4)) != '.sql') {
                    continue;
                }
                $q = $this->db->dsql()
                    ->table('_db_update')
                    ->where('name', strtolower($name))
                    ->field('status');
                if ($q->getOne() === 'ok') {
                    continue;
                }
                $migration = file_get_contents($dir.'/'.$name);
                $q->set('name', strtolower($name));
                try {
                    $this->db->dbh->exec($migration);
                    $q->set('status', 'ok')->replace();
                } catch (Exception $e) {
                    $q->set('status', 'fail')->replace();
                    if (!$e instanceof BaseException) {
                        $e = $this->exception()
                            ->addMoreInfo('Original error', $e->getMessage());
                    }
                    throw $e->addMoreInfo('file', $name);
                }
            }
        }

        return $this;
    }