// Quiz
    public function author()
    {
        return $this->belongsTo('App\User', 'created_by', 'id');
    }

    public function questions()
    {
        return $this->hasMany('App\Models\Question')->with('answers');
    }
// Question
    public function answers()
    {
        return $this->hasMany('\App\Models\Answer');
    }