added prompt to passport input for Google SSO

src/routes/authentication.js

@@ -52,7 +52,8 @@
 			loginStrategies.forEach(function(strategy) {
 				if (strategy.url) {
 					router.get(strategy.url, passport.authenticate(strategy.name, {
-						scope: strategy.scope
+						scope: strategy.scope,
+						prompt: strategy.prompt || undefined
 					}));
 				}