Pups::ExecError: su postgres -c 'psql discourse -c "alter schema public owner to discourse;"' mislukt met retourwaarde

I understand that but you may have a formatting error. The app.yml file us very picky…just one line outbof alignment can cause problems.

This why I mentioned pasting inbetween the code markdown so we can see a raw version of your file.

Something even simple as an empty line between lines can cause a problem.