fix an incorrect docker-gen parameter, other minor fixes to example
fix an incorrect docker-gen parameter, other minor fixes to example

- Needed to fix the incorrect --only-published to -only-published 
- Think it's more likely to work for more people if change -only-published to -only-exposed
- added :ro to the sock, to match your other examples in your other project pages.
appropriate/docker-gen,cybercode/docker-gen,viranch/docker-gen,atyenoria/docker-gen,rashpile/docker-gen,jwilder/docker-gen,Boran/docker-gen,dataferret/docker-gen,baptistedonaux/docker-gen,remh/docker-gen