index: update Matrix info for bitcoinj space, bitcoinj-users, bitcoinj-developers

Author: msgilligan

index.html

@@ -106,5 +106,10 @@ <h1 id="community">Community</h1>
   <li>View <a href="https://github.com/bitcoinj/bitcoinj">bitcoinj on Github</a> - make sure to <q>star</q> us!</li>
   <li>Ask questions and discuss improvements on the <a href="https://groups.google.com/forum/#!forum/bitcoinj">mailing list</a></li>
   <li>Search and report issues on the <a href="https://github.com/bitcoinj/bitcoinj/issues">Issues Data Base</a> (to ask for help please use the mailing list, not the Issues DB)</li>
-  <li>Join our <a href="https://matrix.org">Matrix</a> room: <a href="https://matrix.to/#/#bitcoinj:matrix.org">#bitcoinj:matrix.org</a>.</li>
+  <li>Join our <a href="https://matrix.org">Matrix</a> <i>space</i>: <a href="https://matrix.to/#/#bitcoinj:matrix.org">#bitcoinj:matrix.org</a>, which contains the following:
+    <ul>
+      <li>The <a href="https://matrix.to/#/#bitcoinj-users:matrix.org">#bitcoinj-users:matrix.org</a> <i>room</i> for discussion among developers using bitcoinj in their projects.</li>
+      <li>A bitcoinj-developers room (visible after joining the space) for discussion among developers working on (contributing to) bitcoinj.
+    </ul>
+  </li>
 </ul>