Add a list of Tracker URLs to config

[josecelano]

Currently, you can set the associated tracker URL in the configuration:

[tracker]
url = "udp://tracker.torrust-demo.com:6969"
# ...
token_valid_seconds = 7257600

When you upload a torrent, the Index will include that tracker URL:

It would be nice to include a list of URLs for the same tracker, for example:

• udp://tracker.torrust-demo.com:6969
• http://tracker.torrust-demo.com:7070
• https://tracker.torrust-demo.com:7070

Does it make sense @WarmBeer?

[cgbosse]

@WarmBeer and @da2ce7 we would like your input.

[mickvandijke]

I can't think of a reason why it would be useful to include multiple urls of the same tracker. But it might be useful to include "backup" trackers perhaps?