add fathom

lets try it first, then switch of simpleanalytics if all good

_layouts/default.html

@@ -11,6 +11,22 @@
         <script async defer src="https://cdn.simpleanalytics.io/hello.js"></script>
         <noscript><img src="https://api.simpleanalytics.io/hello.gif" alt=""></noscript>
 
+        <!-- Fathom - simple website analytics - https://github.com/usefathom/fathom -->
+        <script>
+         (function(f, a, t, h, o, m){
+	         a[h]=a[h]||function(){
+		         (a[h].q=a[h].q||[]).push(arguments)
+	         };
+	         o=f.createElement('script'),
+	         m=f.getElementsByTagName('script')[0];
+	         o.async=1; o.src=t; o.id='fathom-script';
+	         m.parentNode.insertBefore(o,m)
+         })(document, window, '//fathom.status.im/tracker.js', 'fathom');
+         fathom('set', 'siteId', 'YELIA');
+         fathom('trackPageview');
+        </script>
+        <!-- / Fathom -->
+      
         <!-- Twitter cards -->
         <meta name="twitter:site"    content="@{{ site.twitter_username }}">
         <meta name="twitter:creator" content="@{{ page.author }}">