pq: could not resize shared memory segment. No space left on device

This is because docker by-default restrict size of shared memory to 64MB.

You can override this default value by using --shm-size option in docker run.

docker run -itd --shm-size=1g postgres

or in docker-compose:

db:
  image: "postgres:11.3-alpine"
  shm_size: 1g

Check this out. More info here.