readme update [CI skip]

README.md

 # Getting started
 This is a project to get started on the gitlab CI for compiling and testing code.
 
+The master branch has a very rudimentary `.gitlab-ci.yml` file to build the project once.
+
+You find the  branches `testlevel*`  with increasing test complexity in the script `.gitlab-ci.yml`.
+
 Important things:
 -  Explanations of the YAML syntax of the file **.gitlab-ci.yml** [found here](https://docs.gitlab.com/ce/ci/yaml)
 - Installation of a local runner [found here](https://docs.gitlab.com/runner/install/)