public function flushConfig($key)
    {
        if (null !== $this->cache) {
            if (isset($this->config[$key]) && array_key_exists('cacheKey', $this->config[$key])) {
                $cacheKey = $this->config[$key]['cacheKey'];
            } else {
                $cacheKey = $this->getCacheKeyForFile($this->getFileNameForKey($key));
            }

            $this->app[$this->cache]->delete($cacheKey);
        }

        unset($this->config[$key]);
    }