List schleuder providers

_includes/navbar.html

@@ -40,6 +40,9 @@
           <a class="navbar-item" href='{{ "schleuder/docs/projects-and-plugins.html" | absolute_url }}'>
             Projects & Plugins
           </a>
+          <a class="navbar-item" href='{{ "schleuder/docs/providers.html" | absolute_url }}'>
+            Providers
+          </a>
         </div>
       </div>
 
@@ -54,4 +57,4 @@
       </a>
     </div>
   </div>
-</nav>
\ No newline at end of file
+</nav>

schleuder/docs/providers.md

+---
+title: Providers of Schleuder lists
+---
+
+To use a Schleuder list, Schleuder must run on a server. You can do that yourself as described in the [documentation for server admins](server-admins.html) or ask a service provider that you trust. The following tech collectives offer schleuder lists upon request.
+
+[immerda.ch](https://www.immerda.ch/) (invite only)
+
+[systemli](https://www.systemli.org/service/schleuder/)
+
+[so36](https://so36.net)