Added docker commands for invoking markdownlint and markdown-link-check.

doc.zih.tu-dresden.de/README.md

@@ -133,6 +133,16 @@ docker run -it hpc-compendium mkdocs serve -a 0.0.0.0:8000
 docker inspect `docker ps | grep hpc-compendium | cut -d' ' -f1` | sed -n '/\<IPAd/s#^.*"\([0-9.]*\)".*$#http://\1:8000#p' | head -n1
 ```
 
+If you want to check whether the markdown files are formatted properly, use the following command:
+```Bash
+docker run -it hpc-compendium markdownlint docs
+```
+
+To check whether there are links that point to a wrong target, use (this may take a while and gives a lot of output because it runs over all files):
+```Bash
+docker run -it hpc-compendium bash -c "find docs -type f -name '*.md' | xargs -L1 markdown-link-check"
+```
+
 #### Build Static Documentation
 
 To build the documentation, invoke `mkdocs build`. This will create a new directory named `public`