private function loadConfigFromBundles(ContainerBuilder $container)
    {
        $config = [];

        foreach ($container->getParameter('kernel.bundles') as $bundleClass) {
            $refClass   = new \ReflectionClass($bundleClass);
            $bundleDir  = dirname($refClass->getFileName());
            $configFile = $bundleDir . '/Resources/config/contao_bootstrap.yml';

            if (file_exists($configFile)) {
                $config = ArrayUtil::merge($config, Yaml::parse(file_get_contents($configFile)));
            }
        }

        $container->setParameter('contao_bootstrap.config', $config);
    }