Add VHOSTS variable to enable multiple queues
Since we are using rabotik_tiles and rabotnik_obm, both need to have their own distinct queues to register to.
That's why we need to add a virtual host for each (extra) queue. These can be accessed by using the following URL: HOST:PORT/VHOST.
So if the rabotnik message bus container name is rabotnik-message-bus, the port is 5672 and the virtual host is rabotnik-tiles, the celery broker host to access the rabbitmq system should be rabotnik-message-bus:5672/rabotnik-tiles.
If we don't do this, multiple programs (rabotnik-tiles and rabotnik_obm) register onto the same queue system and will give errors each time something is put in the queue of the other program. This won't stop them from being functional (because they are not subscribed to the queue), but there will be errors. Don't ask me why, if they are not subscribed, they will still listen to the queues, but they just do.