To build:
* nginx first because it creates selfsigned certificate:
  docker-compose -f sourcearcade.yml build --build-arg SELFSIGNED_REQ_HOST=hostname nginx
  - optionally: --build-arg SELFSIGNED_REQ_ALT_NAMES="DNS:name1 ..."
* docker-compose -f sourcearcade.yml build --build-arg SELFSIGNED_REQ_HOST=hostname
  - same build-args!

Adapt checked in files:
* Set server_name in `nginx/sa.conf`
* Set SIMPLEID_BASE_URL in `simpleid/www/config.php`
* Make sure identities point to the right URL
* Set CANONICAL_WEB_URL in `gerrit/environment`
* Enable GitHub OAUTH in `gerrit/environment`