The documentation at: https://github.com/LibreBooking/app/blob/03d6384ffeb0d6a4112d38bab585e5ad8951a07c/doc/INSTALLATION.md

Is incomplete. For example it doesn't explain about using composer

It would be good to redo the documentation and test the steps to make sure they work. This might also be paired with improvements to the CI to do an installation and do a quick smoke test to make sure it works.