public function show($id)
    {
        try {
            $thread = Thread::findOrFail($id);
        } catch (ModelNotFoundException $e) {
            Session::flash('error_message', 'The thread with ID: ' . $id . ' was not found.');

            return redirect('message');
        }

        // show current user in list if not a current participant
        // $users = User::whereNotIn('id', $thread->participantsUserIds())->get();

        // don't show the current user in list
        $userId = Auth::user()->id;
        $users = User::whereNotIn('id', $thread->participantsUserIds($userId))->get();

        $thread->markAsRead($userId);

        return view('chat.show', compact('thread', 'users'));
    }