add Cron job to Swan scope

[xiaods]

sometime integration a crone job is amazon works. Kala is a simplistic, modern, and performant job scheduler written in Go. It lives in a single binary and does not have any dependencies.

Kala was inspired by the desire for a simpler Chronos (developed by Airbnb). Kala is Chronos for the rest of us.

https://github.com/ajvb/kala