Add sidebar section with links to GET and ref

inc/instance-config.php

@@ -38,6 +38,10 @@
    // Optional for the Categories theme. This is an array of name => (title, url) groups for categories
    // with non-board links.
    $config['custom_categories'] = array(
+      'Our Friends' => array(
+          'GET' => 'https://getchan.net/GET/',
+          'ref' => 'https://getchan.net/ref/'
+      ),
       'Links' => array(
           'New Multitude' => 'https://newmultitude.org/',
           'Booru image repository' => 'https://lefty.booru.org/',