app.js

// Bootstrap routes

fs.readdir(__dirname + '/routes', function(err, files){
  if (err) throw err;
  files.forEach(function(file){
    require('./routes/' + file.replace('.js',''))(app);
  });
});

users.js

module.exports = function(app){
  app.get('/users', function(req, res){
    res.send('Hello users!');
  });
};