add CPS as heroku scheduler example

[fgomez828]

Documentation request

CPS is the first app that we're using heroku scheduler on, so we can add it to our documentation as a reference. Important links:

• Heroku resources page for cps production app here
• We can use this app's readme as a guide for using heroku scheduler, as well. Here is the PR where changes to the README are being made.

[smcalilly]

We have this here: https://github.com/datamade/how-to/blob/88dfa121bd2b9af195580c98bb99e858d9e5496a/deployment/heroku/scheduling-tasks.md#heroku-scheduler