This Docker compose setup provides a nginx reverse proxy based on the excellent nginx-proxy container by Jason Wilder et al. and the companion Let's Encrypt container by Nicolas Duchon, Yves Blusseau et al., all in one.
One simply needs to clone this repository and start everything up with docker-compose using
docker-compose -p proxy up -d
Now you can start your containers providing the environment variables VIRTUAL_HOST (with the hostname used for reverse proxying), LETSENCRYPT_HOST and LETSENCRYPT_EMAIL (with the hostname for the Let's Encrypt certificate and the email address for notify emails).