Merge branch 'master' of https://github.com/ayasyrev/model_constructor

Author: ayasyrev

docs/_layouts/default.html

@@ -38,6 +38,16 @@
         });
 
     </script>
+    <!-- Global site tag (gtag.js) - Google Analytics -->
+    <script async src="https://www.googletagmanager.com/gtag/js?id=UA-158811190-1"></script>
+    <script>
+      window.dataLayer = window.dataLayer || [];
+      function gtag(){dataLayer.push(arguments);}
+      gtag('js', new Date());
+
+      gtag('config', 'UA-158811190-1');
+    </script>
+
     <script>
         $(function () {
             $('[data-toggle="tooltip"]').tooltip()