Add Menu and Navigation

js/index.js

@@ -0,0 +1,12 @@
+import Menu from './menu';
+import Nav from './nav';
+
+document.addEventListener('DOMContentLoaded', () => {
+  const menu = new Menu({
+    el: document.querySelector('.Menu'),
+  });
+  new Nav({
+    el: document.querySelector('.Nav'),
+    menu,
+  });
+});