web/_includes/google-analytics.html

<!--
  The GA snippet
-->
<!-- Global site tag (gtag.js) - Google Analytics -->
<script defer src="https://www.googletagmanager.com/gtag/js?id={{ site.google_analytics.id }}"></script>
<script>
  document.addEventListener("DOMContentLoaded", function(event) {
    window.dataLayer = window.dataLayer || [];
    function gtag(){dataLayer.push(arguments);}

    gtag('js', new Date());
    gtag('config', '{{ site.google_analytics.id }}');
  });
</script>