docker-compose.yml

version: '3'
services:
  db:
    image: postgres:10.0-alpine
    env_file: .env
    volumes:
      - pg-data-volume:/var/lib/postgresql/data
    ports:
      - '${POSTGRES_HOST_PORT}:${POSTGRES_CONTAINER_PORT}'
    networks:
      - my-app-network
volumes:
  pg-data-volume:
networks:
  my-app-network:

.env

POSTGRES_HOST_PORT=5432
POSTGRES_CONTAINER_PORT=5432
POSTGRES_HOSTNAME=db
POSTGRES_USER=username
POSTGRES_PASSWORD=password
POSTGRES_DB=mydb

docker-compose up to bring up services docker-compose down to bring down services docker-compose down -v to delete associated volumes. This deletes db data and initial credentials