Add archive.org.

public/index.html

@@ -12,7 +12,7 @@
 
     <p>
       This is a manually curated list of 'official' Mastodon 
-      instances that have been set up by organisations under their 
+      instances that have been set up by organisations or projects under their 
       own brand / identity.
     </p>
 
@@ -27,8 +27,9 @@
       <li>Germany: <a href="https://social.bund.de/explore ">https://social.bund.de</a></li>
     </ul>
 
-    <h2>NGO</h2>
+    <h2>Non-profit / Social profit / NGO</h2>
     <ul>
+      <li>Archive.org: <a href="https://mastodon.archive.org/explore">https://mastodon.archive.org/explore</a></li>
       <li>...</li>
     </ul>
 
@@ -38,6 +39,11 @@
       <li>...</li>
     </ul>
 
+    <h2>Opensource</h2>
+    <ul>
+      <li>...</li>
+    </ul>
+
     <hr>
 
     <h2>Contributing</h2>