Update app.js

app.js

+app.get('/menu', function(req, res){
+    fs.readdir("public", (err, files) => {
+        let menu = "<h1>My pages</h1><ul>";
+
+        files.forEach(file => {
+          let link = `<li><a href = '/${file}'>${file}</a></li>`
+          menu += link
+        });
+        menu += "</ul>"
+        res.send(menu); 
+      });
+})