add beta site warning

server/server.js

@@ -186,6 +186,12 @@ passportConfigurator.init();
 app.use(rxMiddleware());
 
 app.use(function(req, res, next) {
+  // add beta warning
+  req.flash('info', {
+    msg: `warning: you are on expiramentel branch of Free Code Camp:
+      You're progress here may or may not be saved to the main site`
+  });
+
   // Make user object available in templates.
   res.locals.user = req.user;
   next();