add a link to newsletters

Author: kiyoto

index.html

@@ -55,11 +55,12 @@ <h1 class="logo"><a href="/">Fluentd</a></h1>
           src="/images/treasure-logo-red.png" height="10px" /></a></div>
       <div class="top-holder">
         <ul>
-          <li><a href="http://docs.fluentd.org/">Documentation</a></li>
+          <li><a href="http://docs.fluentd.org/">Docs</a></li>
           <li><a href="http://fluentd.org/plugin/">Plugins</a></li>
-          <li><a href="http://groups.google.com/group/fluentd">MailingList</a></li>
+          <li><a href="http://groups.google.com/group/fluentd">Mailing List</a></li>
           <li><a href="https://github.com/fluent/fluentd/issues">Issues</a></li>
           <li><a href="http://github.com/fluent/fluentd">Source</a></li>
+          <li><a href="http://go.treasuredata.com/Fluentd_education">Sign up for Newsletters</a></li>
         </ul>
         <span class="social-buttons" style="margin-left:20px;">
           <iframe src="http://ghbtns.com/github-btn.html?user=fluent&repo=fluentd&type=watch&count=true"