Add feed.json to head

Author: Diego Fernandez

_includes/head.html

@@ -7,6 +7,7 @@
   <link rel="stylesheet" href="{{ "/assets/css/main.css" | relative_url }}">
   <link rel="shortcut icon" type="image/png" href="{{ "assets/img/favicon.png" | relative_url }}" >
   <link rel="alternate" type="application/rss+xml" title="{{ site.title | escape }}" href="{{ "/feed.xml" | relative_url }}">
+  <link rel="alternate" type="application/json" title="{{ site.title }}" href="{{ "/feed.json" | absolute_url }}">
   <script src="{{ "/assets/js/main.js" | relative_url }}"></script>
   {% if jekyll.environment == 'production' and site.google_analytics %}
     {% include google-analytics.html %}