Two related services

[sandstrom]

Excellent library!

Two related services that could be worth mentioning in the README.

1. GoodJob (https://github.com/bensheldon/good_job), a modern asynchrony job worker.

2. Consul (https://github.com/hashicorp/consul), a service discovery and mesh tool, that also provide a simple distributed lock backed by raft.

   Useful to guarantee that only one instance of Clockwork is running at the same time, while providing fault tolerance.

Just wanted to mention these. You may already know about them. Feel free to close this issue.