How to list and filter related column on Laravel-Admin

I'll try to get question table value from answer table this time.

Code

CREATE TABLE `questions` (
  `id` bigint(20) unsigned NOT NULL AUTO_INCREMENT,
  `content` varchar(191) COLLATE utf8mb4_unicode_ci NOT NULL,
  `created_at` timestamp NULL DEFAULT NULL,
  `updated_at` timestamp NULL DEFAULT NULL,
  PRIMARY KEY (`id`),
);

 CREATE TABLE `answers` (
  `id` bigint(20) unsigned NOT NULL AUTO_INCREMENT,
  `question_id` int(11) NOT NULL,
  `answer` int(11) NOT NULL,
  `created_at` timestamp NULL DEFAULT NULL,
  `updated_at` timestamp NULL DEFAULT NULL,
  PRIMARY KEY (`id`),
);

app/Models/Answer.php

    public function question(){
        return $this->belongsTo(Question::class);
    }

app/Admin/Controllers/AnswerController.php

    protected function grid()                                                      
    {
        $grid = new Grid(new Answer); 
        $grid->column('id', __('Id'))->filter();
        $grid->column('question.content', __('question')); // Here is the point.
        $grid->column('created_at', __('Created at'));

        $grid->filter(function($filter){
            $filter->equal('question.content');
        });

        return $grid;                                                              
    }                                                                              

Reference

One to one
Model grid filters