Ask browsers to not send referrer for external links

app/assets/javascripts/application.js

@@ -19,4 +19,8 @@ $(function() {
   $('input[data-behavior=focus]:first').focus().select();
 
   $('[data-toggle="popover"]').popover({ html: true });
+
+  if ($('meta[name=referrer][content=none]').length > 0) {
+    $('a[href*=http]').attr('rel', 'noreferrer');
+  }
 });