Laravel 5.1 split routes to different files

modify app/Providers/RouteServiceProvider.php

//origin routes files
public function map(Router $router)
    {
        $router->group(['namespace' => $this->namespace], function ($router) {
            require app_path('Http/routes.php');
        });
    }

// add some others routes files
public function map(Router $router)
    {
        $router->group(['namespace' => $this->namespace], function ($router) {
            require app_path('Http/routes.php');
            require app_path('Http/admin_routes.php');
            require app_path('Http/events_routes.php');
         });
    }

each route files will be merged at run time