feat: google tag manager

Author: kyechan99

index.html

@@ -10,7 +10,13 @@
     <script crossorigin src="https://unpkg.com/react@18/umd/react.production.min.js"></script>
     <script crossorigin src="https://unpkg.com/react-dom@18/umd/react-dom.production.min.js"></script>
     <script src="https://unpkg.com/@babel/standalone/babel.min.js"></script>
-
+    <!-- Google Tag Manager -->
+    <script>(function(w,d,s,l,i){w[l]=w[l]||[];w[l].push({'gtm.start':
+      new Date().getTime(),event:'gtm.js'});var f=d.getElementsByTagName(s)[0],
+      j=d.createElement(s),dl=l!='dataLayer'?'&l='+l:'';j.async=true;j.src=
+      'https://www.googletagmanager.com/gtm.js?id='+i+dl;f.parentNode.insertBefore(j,f);
+      })(window,document,'script','dataLayer','GTM-TVJMBBXW');</script>
+    <!-- End Google Tag Manager -->
     <!-- Google tag (gtag.js) -->
     <script async src="https://www.googletagmanager.com/gtag/js?id=G-L1N8GXV3L2"></script>
     <script>
@@ -25,4 +31,8 @@
     <div id="root"></div>
     <script type="text/babel" src="index.js"></script>
   </body>
+  <!-- Google Tag Manager (noscript) -->
+  <noscript><iframe src="https://www.googletagmanager.com/ns.html?id=GTM-TVJMBBXW"
+    height="0" width="0" style="display:none;visibility:hidden"></iframe></noscript>
+  <!-- End Google Tag Manager (noscript) -->
 </html>