UserFrosting中的自定义控制器

我一直在尝试创建一个扩展UserFrosting's BaseController的自定义控制器，然后从index.php调用它的方法。看起来很简单，但到目前为止我非常不成功。我是UserFrosting的新手，因此我很可能错过了一些明显的东西。

控制器/LGController.php:

<?php
namespace UserFrosting;
class LGController extends 'UserFrosting'BaseController {
    public function __construct($app){
        $this->_app = $app;
    }
    public function lgRequestsList(){
        $groups = array('Luke #1', 'Luke #2');
            $this->_app->render('lg-request-list.twig', [
                "groups" => $groups
            ]);
    }
}

index . php:

...
    use UserFrosting as UF;
    $app->get('/lg/requests/?', function () use ($app) {
        $controller = new UF'LGController($app);
        return $controller->lgRequestsList();
    }); 
...

错误:

[Wed Nov 09 15:25:40 2016] [warn] [client 160.34.126.11] mod_fcgid: stderr: Fatal error (1) in /home2/test/public_html/index.php on line 66: Class 'UserFrosting''LGController' not found, referer: http://xxx.co.uk/groups/g/1/auth