public function store(Request $request, $lecture_id)
{
$this->validate($request, ['title' => 'required', 'description' => 'required']);
$lecture = Lecture::find($lecture_id);
//Log::info('$subject_id: '.$lecture->title);
$subject = new Subject();
$subject->title = $request->title;
$subject->description = $request->description;
$subject->lecture()->associate($lecture);
$subject->save();
return redirect('/lectures/' . $lecture_id . '/subjects');
}