function index()
 {
     if (auth()->user()->role_id == 3) {
         $questions = Question::whereIn('product_id', function ($query) {
             $query->select('id')->from('products')->where('user_id', auth()->user()->id)->get();
         })->orderBy('created_at', 'DESC')->get();
     } else {
         $questions = Question::where('user_id', auth()->user()->id)->orderBy('created_at', 'DESC')->get();
     }
     return view('back.questions', compact('questions'));
 }