website: Adding gitter link to the community page

Author: stack72

website/source/community.html.erb

@@ -13,7 +13,10 @@ there are active, dedicated users willing to help you through various
 mediums.
 </p>
 <p>
-<strong>IRC:</strong> <code>#terraform-tool</code> on Freenode
+  <strong>Gitter:</strong> <a href="https://gitter.im/hashicorp-terraform/Lobby">Terraform Gitter Room</a>
+</p>
+<p>
+  <strong>IRC:</strong> Use the <a href="https://irc.gitter.im">Gitter IRC bridge</a>
 </p>
 <p>
 <strong>Mailing list:</strong>