public function store(QuestionRequest $request)
{
$course = Course::findOrFail($request->input('course_id'));
$this->authorize('view-course', $course);
$question = new Question($request->only(['title', 'body']));
$question->course()->associate($course);
$question->user()->associate(auth()->user());
$question->save();
session()->flash('success', 'La pregunta ha sido enviada');
return redirect()->back();
}