KeyCloak with Postgres. Ref: https://github.com/jboss-dockerfiles/keycloak/blob/master/docker-compose-examples/keycloak-postgres.yml

docker-compose.yml

version: "3"

services:
  postgres:
    image: postgres:11.1
    volumes:
      - ./postgres_data:/var/lib/postgresql/data
    environment:
      POSTGRES_DB: keycloak
      POSTGRES_USER: keycloak
      POSTGRES_PASSWORD: keycloak
    restart: always
  keycloak:
    image: jboss/keycloak:4.6.0.Final
    environment:
      DB_VENDOR: POSTGRES
      DB_ADDR: postgres
      DB_DATABASE: keycloak
      DB_USER: keycloak
      DB_PASSWORD: keycloak
      KEYCLOAK_USER: admin
      KEYCLOAK_PASSWORD: admin
    volumes:
      - ./pgdata:/var/lib/postgresql/data
      - ./backups:/backups
    ports:
      - 8080:8080
    depends_on:
      - postgres