backend/app/controllers/QuestionController.php

<?php
namespace app\controllers;

use app\models\Question;
use kernel\Controller;


class QuestionController extends Controller{
    public function actionCreate()
    {
        echo $this->twig->render('question_create.html.twig');
    }

    public function actionGetQuestionsWithAnswers(): array
    {
        return Question::with('AnswerController')->get()->toArray();
    }

    public function actionGetQuestionsWithUsers(): array
    {
        return Question::with('user')->get()->toArray();
    }

    public function actionGetQuestionAnswersUpvotes($question_id)
    {
        return Question::find($question_id)->answers()->with('upvotes')->get()->toArray();
    }

    public function actionViewAllQuestions()
    {
        foreach (Question::all() as $question)
        {
            echo $question->question. "<br>";
        }
    }
}