Bump container to Ubuntu 22.04

README.md

@@ -18,9 +18,27 @@ environment variables:
 
 For deploying, these can be configured in `/etc/playlistd.toml`.
 
-### Container build (Ubuntu 20.04)
+### Container build (Ubuntu 22.04)
 
-`podman run --rm --network=host -v "$PWD":/mnt -w /mnt -e "DATABASE_URL=postgres://jude@127.0.0.1/playlistd" playlistd cargo deb`
+Build the image:
+
+```sh
+podman build -t playlistd-22 -f Containerfile .
+```
+
+Then build the `.deb`. The `sqlx` query macros check queries against a live, migrated database at
+compile time, so the host's Postgres socket is mounted into the container. With rootless podman, the
+container's root maps to your host user, so local peer authentication works without a password:
+
+```sh
+podman run --rm \
+  -v "$PWD":/mnt -w /mnt \
+  -v /var/run/postgresql:/var/run/postgresql \
+  -e DATABASE_URL='postgres://jude@%2Fvar%2Frun%2Fpostgresql/playlistd' \
+  playlistd-22 cargo deb
+```
+
+The package is written to `target/debian/`.
 
 ## How to use