* Use image too in docker-compose

It is possible with version 2 of compose to use both `build` and `image`

* Update docker-compose.yml

* enable commented volume in docker-compose.yml

* Disable unworking Nginx root directory && Mitigating the HTTPoxy Vulnerability

* add my instance to the list

* enable GZIP on nginx.conf

* readd root /home/mastodon/live/public;

must be added to the Sidekiq invokation in your systemd file

The pull queue will handle link crawling, thread resolving, and OStatus
processing. Such tasks are more likely to hang for a longer time (due to
network requests) so it is more sensible to not make the "in-house" tasks
wait for them.

work flawlessly was a nightmare). WARNING: This commit makes the web UI connect to the streaming API instead
of ActionCable like before. This means that if you are upgrading, you should set that up beforehand.

can be processed separately