[readme] Gitlab-Ci update

README.md

@@ -36,17 +36,19 @@ license.
 
 See the file `LICENSE.md` for full copying permissions.
 
-Automated Testing
------------------
 
-[![buildbot badge](https://git.iws.uni-stuttgart.de/buildbot/badges/dumux-master-dune-rel-2-7-clang-full.svg)](https://git.iws.uni-stuttgart.de/buildbot/#/builders)
+Automated Testing
+------------------
+* Master branch (development): [![master build badge](https://git.iws.uni-stuttgart.de/dumux-repositories/dumux-lecture/badges/master/pipeline.svg)](https://git.iws.uni-stuttgart.de/dumux-repositories/dumux-lecture/-/pipelines?page=1&scope=all&ref=master)
+* Latest release: [![release build badge](https://git.iws.uni-stuttgart.de/dumux-repositories/dumux-lecture/badges/releases/3.4/pipeline.svg)](https://git.iws.uni-stuttgart.de/dumux-repositories/dumux-lecture/-/pipelines?page=1&scope=all&ref=releases/3.4)
 
-The simulations in DuMuX-Lecture are tested automated using buildbot.
-The test suite consists of the actual simulations adjusted to smaller run times.
-Click <a href="https://git.iws.uni-stuttgart.de/buildbot/#/builders" target="_blank">here</a>
-to see the latest builds (clicking on a build
-number will show a detailed overview of the build).
 
+DuMu<sup>x</sup> lecture contains test problems for every example that
+are continuously and automatically tested in the GitLab-CI framework (see badges).
+The test suite is based on CTest and can also be built and run manually
+```
+make -j8 build_tests && ctest -j8
+```
 
 [0]: http://dumux.org
 [1]: http://www.hydrosys.uni-stuttgart.de/index.en.php