Ghost in docker mail configuration

version: "3.2"
services:
    blog:
      image: ghost:4-alpine
      environment:
        mail__transport: SMTP
        mail__from: "Your Name your@email.com"
        mail__options__service: Mailgun
        mail__options__host: smtp.mailgun.org
        mail__options__port: 587
        mail__options__secureConnection: 'false'
        mail__options__auth__user: mailgun@user
        mail__options__auth__pass: mailgun_user_password