Deployment policy (CFP prod server)

For now, while we are running on the independent cfp server, deployments are done manually.

1. Tag the relevant revision in Hamakor's pretalx branch https://github.com/Hamakor/pretalx/releases
2. ssh into the server, and upgrade manually, following the example below (documenting deployment of the pycon-il-0.1.0 tag).

# systemctl stop nginx.service
# systemctl stop pretalx-web  pretalx-worker
# su pretalx -
$ . venv/bin/activate
$ cd pretalx
$ #######
$ # At this point I did some git work, which I do not quote, because
$ # it is one-time, and will not have to be repeated. In particular:
$ # * set origin to point to Hamakor instead of goodes.
$ # * configured (--local) a user and email in order to enable stash
$ #######
$ #  And from this point on, back to work...
$ #######
$ git stash  # save changes in src/pretalx/settings.py
$ git checkout master
$ git pull
$ git checkout pycon-il-0.1.0
$ git stash pop # restore the changes
$ python -m pretalx makemigrations
$ python -m pretalx migrate
$ python -m pretalx rebuild
$ ^D
# systemctl start pretalx-web  pretalx-worker
# systemctl start nginx.service