Update docker-compose.yml

[JonoYang]

This PR add a new service in the docker-compose.yml files to run the purldb-scan-queue-worker command.

[JonoYang]

@tdruez I've reverted the docker-compose files I modified and created a new docker-compose.purldb-scan-queue-worker.yml for this.

[tdruez]

@JonoYang There must be a better way than duplicating the whole compose file for a few line additions. Also, this is likely to be out of sync each time we make changes to the original compose file.

Can't we use the "merge", "extend", "include", features of compose? https://docs.docker.com/compose/multiple-compose-files/

What about a simpler filename docker-compose.purldb-queue.yml file including the docker-compose.yml file, such as:

version: "3"

include:
  - docker-compose.yml

services:
  purldb_scan_queue_worker:
    build: .
    command: wait-for-it --strict --timeout=120 web:8000 -- sh -c "
        ./manage.py purldb-scan-queue-worker --async --sleep 3"
    env_file:
      - docker.env
    volumes:
      - .env:/opt/scancodeio/.env
      - /etc/scancodeio/:/etc/scancodeio/
      - workspace:/var/scancodeio/workspace/
    depends_on:
      - db
      - web

[JonoYang]

@tdruez I've renamed the purldb-scan-queue-worker management command to purldb-scan-worker and updated docker-compose.purldb-scan-worker.yml with the changes you suggested.