added permissive CORS header middleware function

Author: MaxBittker

server.js

@@ -23,6 +23,11 @@ app.set('port', (process.env.PORT || 3000));
 app.use('/', express.static(path.join(__dirname, 'public')));
 app.use(bodyParser.json());
 app.use(bodyParser.urlencoded({extended: true}));
+app.use(function(req, res, next) {
+    //set permissive CORS header
+    res.setHeader('Access-Control-Allow-Origin', '*');
+    next();
+});
 
 app.get('/api/comments', function(req, res) {
   fs.readFile(COMMENTS_FILE, function(err, data) {