Stack containing Postgres and Adminer (images coming from dockerhub)

postgres_demo.yml

# Use postgres/example user/password credentials
# Switch 3001 to the port you want to expose on localhost
version: '3.1'

services:

    db:
        image: postgres
        restart: always
        ports:
            - 5432:5432
        environment:
            POSTGRES_PASSWORD: example

    adminer:
        image: adminer
        restart: always
        ports:
            - 3001:8080

run this stack with:

docker stack deploy -c postgres_demo.yml postgres

If you don't have a swarm setup, you will probably have to also run:
docker swarm init