Add Support for caddy Webserver

In order to achieve https with automatic certificate renewal I wrote the following docker-compose file:

caddy:
  image: abiosoft/caddy
  ports:
    - "1180:80"
    - "11443:443"
  volumes:
    - ./Caddyfile:/etc/Caddyfile
    - ./caddy:/root/.caddy
  links:
    - kanboard
kanboard:
  image: leanlabs/kanban:1.6.0
  ports:
    - "7777:80"
  links:
    - redis
  environment:
    - KANBAN_SERVER_HOSTNAME="https://kanboard.xy.com"
    - KANBAN_GITLAB_URL="https://git.xy.com"
    - KANBAN_GITLAB_CLIENT="clientidhere"
    - KANBAN_GITLAB_SECRET="secrethere"
    - KANBAN_REDIS_ADDR=redis:6379
    - KANBAN_SECURITY_SECRET="secret"
redis:
  image: leanlabs/redis:1.0.0
  volumes:
    - ./redisdata:/data

with the following Caddyfile

kanboard.xy.com
tls me@mail.com
proxy / http://kanboard:80

it works, but after authentication, the page reloads every few milliseconds. I guess it has to do something about how caddy handles web sockets.

Do you see any chance of getting this to work? It would be a very nice, and smooth experience this way.