Update header.html

_includes/header.html

@@ -56,6 +56,9 @@
             <li><a href="https://www.reddit.com/r/monero/">{% t menu.reddit %}</a></li>
             <li><a href="https://bitcointalk.org/index.php?topic=583449.0">{% t menu.bitcointalk %}</a></li>
             <li><a href="https://monero.stackexchange.com">{% t menu.stackexchange %}</a></li>
+            <li><a href="https://monero.slack.com/">{% t menu.slack %}</a></li>
+            <li><a href="https://rocket.xmrnation.com/">{% t menu.rocketchat %}</a></li>
+            <li><a href="https://telegram.me/bitmonero">{% t menu.telegram %}</a></li>
             <li class="divider"></li>
             <li class="dropdown-header">{% t menu.irc %}</li>
             <li><a href="irc://chat.freenode.net/#monero">{% t menu.irc-general %}</a></li>