add gtag function

Author: akariv

ui/projects/businessgate/src/index.html

@@ -37,6 +37,8 @@
     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-P448WZ2N');
+    window.dataLayer = window.dataLayer || [];
+    function gtag(){dataLayer.push(arguments);}
   </script>
   <!-- End Google Tag Manager -->