meta name="google-site-verification" content="jqf1tCZK5GNacMhvmThuAB8wHUwUdl9hJnvfNDh9Fho" /
https://support.google.com/analytics/answer/1008080
gtag('set', {'user_id': 'USER_ID'}); // Set the user ID using signed-in user_id.
ga('set', 'userId', 'USER_ID'); // Set the user ID using signed-in user_id.
Global Site Tag Tracking Code (gtag.js):
gtag('set', {'content_group5': 'My Group Name'});
Universal Analytics Tracking Code (analytics.js):
ga('set', 'contentGroup5', 'My Group Name');
Classic Analytics Tracking Code (ga.js):
_gaq.push(['_setPageGroup', 5, 'My Group Name']);
https://support.google.com/analytics/answer/1008080