step 2: setup express server

src/index.js

@@ -0,0 +1,12 @@
+const express = require('express');
+const path = require('path');
+
+const app = express();
+
+const publicDirectoryPath = path.join(__dirname, '../public');
+app.use(express.static(publicDirectoryPath));
+
+const port = process.env.PORT || 8080;
+app.listen(port, () => {
+  console.log(`Server is up on port ${port}.`);
+});