Modules with a custom url fail

[leo-unglaub]

Hey, when you use a custom module with a custom url the link always points to a 404. Here is an example:

class FooBar extends Scaffolding implements Navigable
{
    public function url ()
    {
        return 'foo-bar';
    }
}

When i use FooBar without the url method the url is /foo_bar and works fine but when i change it i get a 404. I am on Laravel 5.6 with everything updated.

Thanks and greetings Leo