Archived in favor of other tools.
MailHog image based on GO repo.
You need some container for sending emails. Set up in it pass for mailhog (/usr/sbin/sendmail -i -t mailhog:1025), example of running:
docker run -v /hostDir:/var/www/localhost/htdocs -d -p 8025:8025 --name mailhog --link php-fpm-sender lordius/alpine-mailhog
Visit localhost:8025 or IP:8025 where is container with port 4040 is for checking emails.
See Docker Compose LAMP.