diff --git a/server/social.coffee b/server/social.coffee
index 25b7593..25a77a8 100644
--- a/server/social.coffee
+++ b/server/social.coffee
@@ -288,6 +288,7 @@ module.exports = exports = (log, loga, argv) ->
     app.get('/auth/google', passport.authenticate(googleStrategyName, { scope: [
       'https://www.googleapis.com/auth/plus.profile.emails.read'
       ]}))
+    # see https://developers.google.com/identity/protocols/OpenIDConnect#authenticationuriparameters for details of prompt...
     app.get('/auth/google/callback',
       passport.authenticate(googleStrategyName, { prompt: 'select_account', successRedirect: '/auth/loginDone', failureRedirect: '/auth/loginDialog'}))