initial commit for generating the api documentation via phpdocumentor

.gitlab-ci.yml

@@ -3,7 +3,7 @@ stages:
   - build
 
 git checkout:
-  image: alpine/git:latest
+  image: bitnami/git:latest
   stage: checkout
   script:
     - git -c http.sslVerify=false clone https://gitlab.studip.de/studip/studip.git --single-branch