docker-compose for postgres with db init script

postgres:
  image: postgres
  volumes:
    - ./init.sql:/docker-entrypoint-initdb.d/init.sql

Multiple scripts run in alphabetical order, thus it's good practice to prefix them with a number.

volumes:
  - ./schema.sql:/docker-entrypoint-initdb.d/1-schema.sql
  - ./data.sql:/docker-entrypoint-initdb.d/2-data.sql

volumes:
  - ./init-scripts:/docker-entrypoint-initdb.d