public function open($slug)
 {
     $thread = Thread::whereSlug($slug)->closed()->first();
     if (!$thread) {
         return redirect()->back()->with('error', 'This thread is already open.');
     }
     $thread->status = 'Open';
     if (!$thread->save()) {
         return redirect()->back()->with('error', 'There was an issue opening the thread.');
     }
     return redirect()->back()->with('success', 'Thread opened.');
 }