public function enableInteractive($password, $directory = 'data')
    {
        $this->copy(__DIR__.'/static/interactive.php');

        $this->addHook(function($document) {
            $jss = array('slidey.interactive.js', 'slidey.poll.js');

            foreach ($jss as $js) {
                $document->addJs('/slidey/js/'.$js);
            }
        });

        $this->interactive = array(
            'password' => sha1($password),
            'directory' => $directory,
            'key' => uniqid('slidey_'),
            'polls' => '/tmp/polls/',
        );

        $this->mkdir($directory);

        return $this;
    }