https://stackoverflow.com/questions/77941756/how-do-i-add-pg-repack-to-a-postgres-container
Side note: The way it is done in the answer will create 2 intermediate images that will be part of the image, but are completely useless (the apt update/install and apt remove). To do it properly, you do it the way Pleroma's Dockerfile is structured. (Build in a separate `FROM XYZ as build` and then copy only what is needed to the Postgres image. [The last FROM declaration in a Dockerfile is the base for resulting image.])