Document querying single Job by ID

[johtso]

I'm assuming it's as simple as instantiating a Job object with the relevant job id, but the documentation doesn't mention that approach, only using Job references that are returned when they are first created. Also what happens if the job doesn't exist?

[samuelcolvin]

yes it's very simple, you also need to pass a redis instance:

https://github.com/samuelcolvin/arq/blob/cca11e46b7c8ebbd5e17eae1ca3b51eb8739feb7/arq/jobs.py#L64-L70

PR welcome to add this to the docs.