Adding a GridField to SiteConfig

CustomConfig.php

Add the following lines to the bottom of updateCMSFields();
 
<?php

               $fields->addFieldToTab('Root.Quotes', 
                       GridField::create('Quotes', 'Quotes',
                               InspirationalQuote::get(),
                               GridFieldConfig_RecordEditor::create())
               );

Footer.ss

Add this code

	<% with RandomQuote %>
	<p>$Quote<br>
	 — $Author</p>
	<% end_with %>

InspirationalQuote.php

<?php

class InspirationalQuote extends DataObject
{
	private static $db = array(
		"Quote" => "Text",
		"Author" => "Varchar",
	);

	private static $summary_fields = array(
		"Quote",
		"Author"
	);
}

Page.php

Add this to Page_Controller.php

<?php

	public function RandomQuote() {
		return InspirationalQuote::get()->sort('RAND()')->first;
	}