As you can see, Marcus reviewed my patch, and approved it. I am not sure if they have configured to have Gerrit automatically push to GitHub, but that is an option.
It turns out I could not find documentation how to set up Gerrit for a GitHub project, but ended up installing it. That basically consists of setting up MySQL (or equivalent) with a user account and database, create a Linux account, and then follow the install instructions in a .war file. Next then is to register an account, and it nicely picks up a Google Account, but OpenID seems supported too. The first account is automatically the administration account, and that is a good choice indeed.
Finding the right documentation for creating a new project from an existing project was tricky, and I ended up with this instruction. However, typing the second step in that:
git push ssh://egonw@localhost:29418/cdk *:*
causes this output:
Counting objects: 181366, done.
Delta compression using up to 2 threads.
Compressing objects: 100% (32350/32350), done.
fatal: Unpack error, check server log 4.30 MiB | 8.54 MiB/s
error: pack-objects died of signal 13
error: failed to push some refs to 'ssh://egonw@localhost:29418/cdk'
Caused by: java.io.IOException: Invalid tree 00ba05c8a75c3fdd3022fd87d92694e87556acb8:mode starts with '0'
... 15 more
Update: I figured out how to set up a git repository manually on the Gerrit server, and managed to to push a patch for review: