doc: add jenkins docker build job
see
@@ -99,6 +99,7 @@ Then one of the admins (sorted by activity):
- @sanssecours
- @markus2330
- @beku
+- @BernhardDenner
- @fberlakovich
- @manuelm
@@ -150,6 +151,7 @@ After being added to whitelist you can trigger buildjobs by saying:
* jenkins build [homepage](https://build.libelektra.org/job/elektra-homepage/) please
* jenkins build [gcc-configure-debian-stretch-minimal](https://build.libelektra.org/job/elektra-gcc-configure-debian-stretch-minimal/) please
* jenkins build [gcc-configure-debian-jessie-minimal](https://build.libelektra.org/job/elektra-gcc-configure-debian-jessie-minimal/) please
+* jenkins build [docker](https://build.libelektra.org/job/test-docker/) please
### Run All Tests
