public function getTables()
    {
        $tables = [
            0 => [
                'group' => 'Post Type',
                'options' => []
            ],
            1 => [
                'group' => 'Others',
                'options' => [
                    ['label' => 'Users', 'name' => 'users', 'belongsTo' => 'User'],
                ]
            ]
        ];
        // loop throw post types
        foreach(PostType::all() as $postType){
            $tables[0]['options'][] = ['label' => $postType['name'], 'name' => $postType['slug'], 'belongsTo' => 'PostType'];
        }
        return $tables;
    }