add matrix link for the IRC chat

index.html

@@ -112,7 +112,7 @@ h5 {
 }
 </style>
 <div style="float:right; position:fixed; top:.5em; right:.5em;">
-<p><a href="https://github.com/plaintextaccounting/plaintextaccounting.github.io"><img src="https://img.shields.io/github/stars/plaintextaccounting/plaintextaccounting.github.io.svg?style=social&amp;label=Github" title="send pull requests, bug reports, blog posts, star us, tweet with #plaintextaccounting tag" alt="github" /></a></p>
+<p><a href="https://github.com/plaintextaccounting/plaintextaccounting.github.io"><img src="https://img.shields.io/github/stars/plaintextaccounting/plaintextaccounting.github.io.svg?style=social&amp;label=Github" alt="github" title="send pull requests, bug reports, blog posts, star us, tweet with #plaintextaccounting tag" /></a></p>
 </div>
 <div id="section1">
 <h1 id="plain-text-accounting">plain text accounting</h1>
@@ -280,7 +280,7 @@ getting-started.md
 <div class="three columns u-pull-left">
 <h5 id="mail-listsirc">mail lists/IRC</h5>
 </div>
-<p><a href="https://kiwiirc.com/nextclient/#ircs://irc.freenode.net/#plaintextaccounting">#plaintextaccounting</a>, <a href="#plain-text-accounting-tools">project mail lists/chats</a></p>
+<p><a href="https://kiwiirc.com/nextclient/#ircs://irc.freenode.net/#plaintextaccounting" title="&lt;a href=&quot;https://matrix.to/#/#freenode_#plaintextaccounting:matrix.org&quot;&gt;#freenode_#plaintextaccounting:matrix.org&lt;/a&gt; on Matrix">#plaintextaccounting</a>, <a href="#plain-text-accounting-tools">project mail lists/chats</a></p>
 </div>
 <!-- row -->
 <div class="row">

index.md

@@ -444,6 +444,7 @@ getting-started.md
 [project mail lists/chats](#plain-text-accounting-tools)
 
 [#plaintextaccounting]: https://kiwiirc.com/nextclient/#ircs://irc.freenode.net/#plaintextaccounting
+(<a href="https://matrix.to/#/#freenode_#plaintextaccounting:matrix.org">#freenode_#plaintextaccounting:matrix.org</a> on Matrix)
 
  </div> <!-- row -->
  <div class="row">