nixpkgs/pkgs/servers/web-apps/discourse/how_to_update.md

To update discourse, do the following:

1. Switch to and work from the master branch and the directory this file is in.
2. Run ./update.py print-diffs and update the nginx settings and backend settings accordingly. If you don't know how to, ask for help - do not skip this step!
3. Run ./update.py update.
4. Run nix build -L -f ../../../../ discourse.tests to make sure the update works. Also test manually, if possible.
5. If the update works, commit it. If not, apply necessary fixes and commit. No manual fixes that would be overwritten by the ./update.py script should be committed - the script should be fixed instead.
6. Run ./update.py update-mail-receiver. If there's an update, do step 4 and 5 again.
7. Run ./update.py update-plugins.
8. Run nix build -L -f ../../../../ discourseAllPlugins.tests to make sure the plugins build and discourse starts with them. Also test manually, if possible.
9. If the update works, commit it. If not, apply necessary fixes and commit. No manual fixes that would be overwritten by the ./update.py script should be committed - the script should be fixed instead.