[readme] Add buildbot link and description

README.md

@@ -36,6 +36,15 @@ license.
 
 See the file `LICENSE.md` for full copying permissions.
 
+Automated Testing
+-----------------
+
+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).
+
 
 [0]: http://dumux.org
 [1]: http://www.hydrosys.uni-stuttgart.de/index.en.php