Illuminate\Routing\UrlGenerator::forceRootUrl PHP Method

    public function forceRootUrl($root)
    {
        $this->forcedRoot = rtrim($root, '/');
        $this->cachedRoot = null;
    }

 /**
  * Set the forced root URL.
  *
  * @param string $root
  * @return void 
  * @static 
  */
 public static function forceRootUrl($root)
 {
     \Illuminate\Routing\UrlGenerator::forceRootUrl($root);
 }