Create a post announcing and explaining Kroki usage

_posts/2021/05/2021-05-26-diagrams-from-textual-descriptions.md

@@ -8,7 +8,7 @@ layout: blogpost
 categories:
   - tutorials
 excerpt: >
-    Recently, the Helmholtz-wide software development platform has been extended
+    Recently, the Helmholtz-wide software development platform (<a href="https://gitlab.hzdr.de">Gitlab</a>) has been extended
     with the ability to create diagrams from textual descriptions.
     This post will help you getting started with this new feature.