added rss feed tag

_includes/head.html

@@ -13,4 +13,5 @@
   <link rel="stylesheet" type="text/css" href="{{ "/bootstrap/css/bootstrap.css" | prepend: site.baseurl }}">
   <link rel="stylesheet" type="text/css" href="{{ "/css/style.css" | prepend: site.baseurl }}">
   <link href="{{ "/css/font-awesome.min.css" | prepend: site.baseurl }}" rel="stylesheet">
+  <link rel="alternate" type="application/rss+xml" href="feed.xml">
 </head>