Relationship field in user registration

Hi Long,

I have been following this documentation to edit the default fields: https://docs.metabox.io/extensions/mb-user-profile/#edit-default-fields

I want to include a relationship field within the order. However, it doesn't work when I try to add it as a new field.

I am adding it like this:

	[ 'name'          => __( 'University', 'your-text-domain' ),
			   'type' => 'select',
			    'id'   => 'university_user',
        'from' => [
            'object_type' => 'post',
            'post_type'   => 'university',
                'max_clone'  => '1',
            ],
			        ],
        'to'   => [
            'object_type' => 'user',
            'post_type'   => 'post',
            'taxonomy'    => 'category',
		],],

What am I doing wrong?