Initial commit and post-hook testing

blog.bryanroessler.com/_includes/gtm_head.html

@@ -0,0 +1,9 @@
+{% if site.gtm %}
+    <!-- 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','{{ site.gtm }}');</script>
+    <!-- End Google Tag Manager -->
+{% endif %}