Convert cjs import to es6 imports

src/app.js

-var express = require('express');
-var path = require('path');
-var cookieParser = require('cookie-parser');
-var logger = require('morgan');
+import express from 'express';
+import path from 'path';
+import cookieParser from 'cookie-parser';
+import logger from 'morgan';
 
-var indexRouter = require('./routes/index');
-var usersRouter = require('./routes/users');
+import indexRouter from './routes/index';
+import usersRouter from './routes/users';
 
 var app = express();
 
@@ -17,4 +17,4 @@ app.use(express.static(path.join(__dirname, '../public')));
 app.use('/', indexRouter);
 app.use('/users', usersRouter);
 
-module.exports = app;
+export default app;

src/routes/index.js

-var express = require('express');
+import express from 'express';
 var router = express.Router();
 
 /* GET home page. */
@@ -6,4 +6,4 @@ router.get('/', function(req, res, next) {
   res.render('index', { title: 'Express' });
 });
 
-module.exports = router;
+export default router;

src/routes/users.js

-var express = require('express');
-var router = express.Router();
+import express from 'express';
+const router = express.Router();
 
 /* GET users listing. */
 router.get('/', function(req, res, next) {
   res.send('respond with a resource');
 });
 
-module.exports = router;
+export default router;