gistfile1.php

<?php

class CarouselImage extends DataObject {

	public static $db=array(
		'Title'=>'Varchar',
		'SortOrder'=>'Int'
	);

	public static $default_sort='SortOrder';

	private static $has_one = array(
		'Image' => 'Image'
	);

	public function getCMSFields() {

		$uploadField = new UploadField('Image');
		$uploadField->setFolderName('Uploads/Carousel');
		$fields = new FieldList(array(new TextField('Title'),$uploadField));
		return $fields;
	}
}

class CarouselImageAdmin extends ModelAdmin {
	private static $managed_models = array('CarouselImage');
	private static $url_segment = 'carouselimages';
	private static $menu_title = 'Carousel Images';

	public function getEditForm($id = null, $fields = null) {
		/** @var CMSform $form */
		$form      = parent::getEditForm($id, $fields);
		$gridField = new GridFieldSortableRows('SortOrder');


		$form->Fields()->items[0]->config->addComponent($gridField);
		return $form;
	}
}