Remove sidekiq worker.

Work in progress: tests need fixing, but it's possible the necessary changes are done.  Could do with some refactoring afterwards, but it would be nice to keep refactoring in a separate commit.
Removes Sidekiq
Ensure Redis is using namespaces
Remove comment and unnecessary return
Merge pull request #29 from alphagov/remove-sidekiq-worker

Remove sidekiq worker

https://www.pivotaltracker.com/story/show/82200576
Initialize Redis as a service
Ensure Redis is using the configured namespace

* Removes mock_redis gem
Merge pull request #30 from alphagov/use-redis-as-service

Use redis as service