create simple test smtp server

docker-compose.yml

version: '2'

services:
  imap:
    image: antespi/docker-imap-devel:latest
    container_name: imap
    ports:
    - "25:25"
    - "143:143"
    - "993:993"
    environment:
    - MAILNAME=example.org
    - MAIL_ADDRESS=address@example.org
    - MAIL_PASS=pass
  rainloop:
    image: ahmet2mir/rainloop
    mem_limit: 256m
    ports:
      - 8080:80
    links:
      - "imap:mailserver"