/**
  * Substitute the route bindings onto the route.
  *
  * @param  \Routing\Route  $route
  * @return \Routing\Route
  */
 protected function substituteBindings($route)
 {
     foreach ($route->parameters() as $key => $value) {
         if (isset($this->binders[$key])) {
             $route->setParameter($key, $this->performBinding($key, $value, $route));
         }
     }
     return $route;
 }