public function addToCache($key, SiteConfig $config)
    {
        $key = strtolower($key);
        if ('www.' === substr($key, 0, 4)) {
            $key = substr($key, 4);
        }

        if ($config->cache_key) {
            $key = $config->cache_key;
        }

        $this->cache[$key] = $config;

        $this->logger->info('Cached site config with key: {key}', ['key' => $key]);
    }