ruby-clockwork binary package in Ubuntu Bionic amd64

 Clockwork is a cron replacement. It runs as a lightweight,
 long-running Ruby process which sits alongside your web processes
 (Mongrel/Thin) and your worker processes (DJ/Resque/Minion/Stalker)
 to schedule recurring work at particular times or dates.
 .
 For example, refreshing feeds on an hourly basis, or send reminder
 emails on a nightly basis, or generating invoices once a month on the
 1st.

Source package