Add link to public Telegram group

cyberspace.md

@@ -18,6 +18,16 @@ However, and this is important, this open space should be in
 
 Meatspace doesn't scale. Cyberspace does.
 
+## Easy to Join
+
+The group should be open to the public and easy to join. Like this:
+
+<center>
+    <a href="https://t.me/twentyonedotworld" target="_blank">
+        <button type="button" class="btn btn-primary btn-large btn-custom">Join the Group</button>
+    </a>
+</center>
+
 ## Cyberspace
 
 Use whatever works. Here is what worked for others:

network.md

@@ -6,6 +6,15 @@ title: Network
 The "network" part is very much a work-in-progress. If you've started a fork
 and/or would like to help, please [contact me](https://dergigi.com/contact).
 
+If you want to hang out with like-minded people and understand more about the
+concept, feel free to join the open group of twentyone.world:
+
+<center>
+    <a href="https://t.me/twentyonedotworld" target="_blank">
+        <button type="button" class="btn btn-primary btn-large btn-custom">Join the Group</button>
+    </a>
+</center>
+
 List of existing "twentyone" forks:
 
 {% assign communities = "" | split: ',' %}