#81 add Markdown class

- link check functionality
- test class

src/com/cloudogu/ces/cesbuildlib/Markdown.groovy

@@ -0,0 +1,20 @@
+package com.cloudogu.ces.cesbuildlib
+
+class Markdown implements Serializable{
+    Sh sh
+    private script
+    Docker docker
+
+    Markdown(script) {
+        this.sh = new Sh(script)
+    }
+
+    def check(){
+        docker.image("ghcr.io/tcort/markdown-link-check:stable")
+            .mountJenkinsUser()
+            .inside('--entrypoint="" -v ${WORKSPACE}/docs:/tmp') {
+                script.sh 'find /tmp -name \\*.md -print0 | xargs -0 -n1 markdown-link-check -v'
+            }
+    }
+
+}

test/com/cloudogu/ces/cesbuildlib/MarkdownTest.groovy

@@ -0,0 +1,5 @@
+package com.cloudogu.ces.cesbuildlib
+
+class MarkdownTest extends GroovyTestCase {
+
+}