Implement a way to update the seeder address on the tracker

[aburdulescu]

Problem:

If the seeder changes its address, the tracker will not be aware of this change and it will store the invalid address.

Solution:

Each seeder sends to the tracker a unique ID(based on its MAC maybe? or a hash of a private key?) along with its address.
When the seeder changes address, it sends it and the ID to the tracker and the tracker updates the address for the corresponding ID.

[aburdulescu]

Use google/uuid for ID and save it on disk.