Creating a URL with a FK

I'm trying to create a url which reads www.localhost/forum/{slug}/thread={id} but im encountering problems. The {id} part is coming back as that is the thread id but the {slug} part i'm trying to retrieve through a foriegn key and get the issue.

Call to a member function forums() on null

here are my tables Forum: id, name, slug, timestamps Thread: id, name, forum_id, user_id

here is my relation on my thread model

public function forums(){
    return $this->belongsTo('App\Forum');
}

and here is my code on my ThreadController

    public function show($id, $slug)
{
    //
    $thread = Thread::find($id);
    $thread->forums()->slug = $slug;

    return view('forum.thread')->withThread($thread);
}

Any ideas on how i get the Forum's slug into the URL?

via Chebli Mohamed