[DOC] Add README.md

Change-Id: I8455ed2bb673c2223652d80644ce2711fdea2280
Reviewed-on: http://saros-build.imp.fu-berlin.de/gerrit/1580
Tested-by: Jenkins CI
Reviewed-by: Bernd Bieber <brotlee@zedat.fu-berlin.de>
Reviewed-by: Damla Durmaz <ddurmaz88@gmail.com>
Reviewed-by: Franz Zieris <zieris@inf.fu-berlin.de>