How do I add Worker Processes?
Heroku and others allow you to specify different types of processes under a single app such as workers that pull work from a queue.
With Elixir, that is rarely needed since you can spawn asynchronous tasks within your application itself. Elixir and OTP provide all the tools you need to do this type of stuff among others. For more information, see Background Jobs in Phoenix.
If you really need to run an Redis-backed queue to process jobs, take a look at Exq, but consider whether you really need Exq.