LandingPage.php

<?php
class LandingPage extends Page {
	private static $many_many = array(
		'Article' => 'Article'
	);
	public function getCMSFields() {
		$fields = parent::getCMSFields();
		$allArticles = new GridField(
			'GridLink',
			'All Articles',
			$this->Article(),
			GridFieldConfig_RelationEditor::create()
		);
		$fields->addFieldToTab('Root.Articles', $allArticles);
		return $fields;
	}
}
class LandingPage_Controller extends Page_Controller {
}