Add a link checker script

.gitignore

@@ -1,4 +1,5 @@
 /_venv
 /site
 /.vscode
-/.cache
+/.cache
+.lycheecache

README.md

@@ -43,3 +43,9 @@ For larger changes:
 * Access http://127.0.0.1:8000 - any changes to the sources should be
   immediately visible in your browser
 * Open a PR with your changes or just push them if you have commit rights
+
+### Link Checker
+
+Run `./linkcheck.sh` to check for broken links. This script uses
+[lychee](https://github.com/lycheeverse/lychee) and requires Docker to be
+installed.

linkcheck.sh

@@ -0,0 +1,9 @@
+#!/bin/bash
+
+set -e
+DIR="$( cd "$( dirname "$0" )" && pwd )"
+cd "${DIR}"
+
+# touch for permissions
+touch .lycheecache
+docker run --init -it --rm -w /website -v $(pwd):/website lycheeverse/lychee .

lychee.toml

@@ -0,0 +1,7 @@
+cache = true
+max_cache_age = "1d"
+
+scheme = ["https", "http"]
+exclude_all_private = true
+exclude = [
+]