laravel/app/providers/RouteServiceProvider.php

<?php namespace Providers;

use Illuminate\Routing\RouteServiceProvider as ServiceProvider;

class RouteServiceProvider extends ServiceProvider {

	/**
	 * Called before routes are registered.
	 *
	 * Register any model bindings or pattern based filters.
	 *
	 * @return void
	 */
	public function before()
	{
		//
	}

	/**
	 * Define the routes for the application.
	 *
	 * @return void
	 */
	public function map()
	{
		$this->app->booted(function()
		{
			require app('path').'/routes.php';
		});
	}

}