app-config.local.yaml

backend:
  database:
    client: pg
    connection:
      host: localhost
      port: 5432
      user: postgres
      password: postgres

docker-compose.yaml

version: "3.7"

services:
  postgres:
    image: "postgres:12"
    restart: always
    environment:
      POSTGRES_USER: postgres
      POSTGRES_PASSWORD: postgres
      POSTGRES_INITDB_ARGS: "--encoding=UTF8"
    ports:
      - "5432:5432"
    volumes:
      - ./.data:/var/lib/postgresql/data