Generate a postgis container

docker-compose-postgis.yml

version: '3.7'
services:
    postgis:
        image: postgis/postgis:12-3.1
        restart: always
        environment:
          - POSTGRES_USER=demo
          - POSTGRES_PASSWORD=demo
          - POSTGRES_DB=demo
        ports:
          - '5432:5432'
        extra_hosts:
            - "host.docker.internal:host-gateway"