Update to the new NUR format
See https://github.com/nix-community/NUR/issues/45
Add not about travis cron jobs
No need to export $outs
It actually hid the error code
cachix username -> cache name
Trigger NUR update only on master builds
Mention the cachix private key
Initial commit
Extracted the skeleton from https://github.com/fgaz/nur-packages.git