public function exportAction()
    {
        $this->checkGame();
        $content = serialize($this->game);

        $response = $this->getResponse();
        $headers = $response->getHeaders();
        $headers->addHeaderLine('Content-Encoding: UTF-8');
        $headers->addHeaderLine('Content-Type', 'text/plain; charset=UTF-8');
        $headers->addHeaderLine(
            'Content-Disposition',
            "attachment; filename=\"". $this->game->getIdentifier() .".txt\""
        );
        $headers->addHeaderLine('Accept-Ranges', 'bytes');
        $headers->addHeaderLine('Content-Length', strlen($content));
    
        $response->setContent($content);
    
        return $response;
    }