refactor(i18n): add comments

src/controllers/auth.js

@@ -88,7 +88,7 @@ api.registerUser = function(req, res, next) {
           timestamps: {created: +new Date(), loggedIn: +new Date()}
         }
       };
-      user.language = req.language;
+      user.language = req.language; // User language detected from browser, not saved
       user = new User(newUser);
 
       // temporary for conventions
@@ -258,7 +258,7 @@ api.setupPassport = function(router) {
           if (user) return cb(null, user);
 
           user = new User({
-            language: req.language,
+            language: req.language, // User language detected from browser, not saved
             auth: {
               facebook: req.user,
               timestamps: {created: +new Date(), loggedIn: +new Date()}