Add Telegram overview

src/includes/template.pug

@@ -28,6 +28,7 @@ html(lang="en")
                 a(href="/meetups/" class=(navCurrent === 'meetups' && 'current')) Meetups
                 a(href="/events/" class=(navCurrent === 'events' && 'current')) Events
                 a(href="/spenden/" class=(navCurrent === 'spenden' && 'current')) Spenden
+                a(href="/telegram/" class=(navCurrent === 'telegram' && 'current')) Telegram
                 a(href=site.meta.youtubeUrl target="_blank" rel="nofollow noopener") YouTube
                 a(href=site.meta.shoutoutUrl target="_blank" rel="nofollow noopener") Shout-Out
             .navItem

src/telegram.pug

@@ -0,0 +1,20 @@
+extends /template.pug
+
+block vars
+  - const title = 'Telegram-Gruppen'
+  - const description = 'Eine Liste von Telegram-Gruppen der Einundzwanzig Community.'
+
+block main
+  #telegram.wrap
+    section
+      h1= title
+      p= description
+
+      :markdown-it(html linkify typographer)
+        Neue Meetups können gerne [per Pull Request](https://github.com/Einundzwanzig-Podcast/einundzwanzig.space/edit/master/content/telegram.json) hinzugefügt werden.
+        Hier gibt es ein [Video-Tutorial](https://www.youtube.com/watch?v=BNJc9LExEzU), wie ein neuer Pull Request erstellt werden kann.
+
+      ul
+        each group in telegram
+          li
+            a(href=group.url rel="nofollow noopener" target="_blank")= group.name