public function configureTwigBundle(ContainerBuilder $container, array $config)
    {
    	foreach(array_keys($container->getExtensions()) as $name) {
    		switch($name) {
    			case 'twig':
    				$container->prependExtensionConfig($name, array(
    					'form_themes' => array($config['form_theme'])
    				));
    				break;
    		}
    	}
    }