server.js

const express = require('express');
const app = express();
const historyAPIFallback = require('connect-history-api-fallback');
const SnapHandler = require('luis').handler;

app.use('/snapshot', SnapHandler);
app.use(historyAPIFallback());

// make sure that server.js is in your project root
app.use(express.static('louis'));
app.listen(9001, function () {
    console.log('Example app listening to you on port 9001!');
});