Before middleware inside mount() that works for / and /.*

Hey,

let's say I have the following route :
```php
$router->get('/', 'HomepageController@index');
```
I would like to use the before route middleware to restrict non-logged in users from accessing the website. So I did this :
```php
$router->before('GET', '/.*', 'AuthController@login');
```
The problem is that this doesn't work for the **'/'** route, but **'/blablabla'** for example.

Is there a subpattern or something else that allows my application to restrict non-logged in users using before route middleware in 1 single line rather than doing like this ?
```php
$router->before('GET', '/', 'AuthController@login');
$router->before('GET', '/.*', 'AuthController@login');
```

My idea would be to add a before route middleware to the **mount()** method so all routes inside this method will call first **AuthController@login**.

Start by reading the router's before() and mount() entry points and trace how the '/' and '/.*' patterns are matched. Done means a before middleware configured for a mount applies to every route inside it, including the root route, with behavior checked for both examples.

Written by the indexing model from the issue text.