Add support for docker secrets via FILE__ variables - #501

# compose.yaml: Replace the vars by FILE__ vars and add docker secrets
services:
  voidauth: 
    image: voidauth/voidauth:latest
    restart: unless-stopped
    volumes:
      - ./voidauth/config:/app/config
      # Only required for declaring OIDC Apps via docker labels (see OIDC-Setup documentation)
      # - /var/run/docker.sock:/var/run/docker.sock:ro
    ports:
      - "3000:3000" # may not be needed, depending on reverse-proxy setup
      # - "3890:3890" # only needed if LDAP Server is enabled
    environment:
      # Required environment variables
      # See https://voidauth.app/#/Getting-Started?id=environment-variables for a list of possible environment variables
      APP_URL: # required
      DB_ADAPTER: postgres # this is the default value
      DB_HOST: voidauth-db # required
      FILE__DB_PASSWORD: /run/secrets/db_password
      FILE__STORAGE_KEY: /run/secrets/storage_key
    secrets:
      - db_password
      - storage_key
    depends_on:
      voidauth-db:
        condition: service_healthy

  voidauth-db:
    image: postgres:18
    restart: unless-stopped
    environment:
      POSTGRES_PASSWORD_FILE: /run/secrets/db_password
    ports:
      # NOTE: Had to map the port to access via localhost for local development
      - 54320:5432
    volumes:
      - ./voidauth/db:/var/lib/postgresql/18/docker
    secrets:
      - db_password
    healthcheck:
      test: "pg_isready -U postgres -h localhost"

secrets:
  db_password:
    file: ./secrets/db_password
  storage_key:
    file: ./secrets/storage_key