Document stages and jobs.

docs/gitlab/drupal/index.md

@@ -195,6 +195,27 @@ The following jobs must run before successfully:
 
 #### Check 4 Updates
 
+e start a docker image for `php` with the specifies versions:
+
+- `PHP_MAJOR_VERSION`
+- `PHP_MINOR_VERSION`
+
+First we have to do some preparation. This is done in the `before_script` section.
+
+- [.prepareaccess](#prepareaccess)
+- [.preparecomposerplugins](#preparecomposerplugins)
+
+The job stores the artefacts in `check4updates`.
+
+
+
+
+Rules, when the job should run:
+
+- `$CHECKUPDATES` is set
+- we are on the `develop` branch
+
+
 #### Check 4 Outdated Packages
 
 We start a docker image for `php` with the specifies versions: