Following instructions results in "no such app"

[kylebragger]

I followed the instructions exactly for this demo and the resulting dockhero.io URL yields the "no such app" Heroku error page.

Steps to repro:

1. heroku addons:create dockhero
2. heroku plugins:install dockhero
3. heroku dh:wait
4. heroku dh:compose up -d
5. heroku logs --tail -p dockhero
6. heroku dh:open

dockhero-compose.yml:

version: "2"

services:
  proxy:
    image: dockhero/caddy-proxy
    restart: "on-failure:10"
    ports:
      - "80:80"
      - "80:80/udp"
      - "443:443"
      - "443:443/udp"
    volumes:
      - caddy_certificates:/srv
    environment:
      VIRTUAL_HOSTS: https://${DOCKHERO_HOST}
      TARGET_URL: ${HEROKU_APP_URL}

volumes:
  caddy_certificates:
    driver: local

Everything is deployed and the app is otherwise accessible on Heroku.