As a part of test environment, an unprivileged redis server is started on localhost:6379.
Redis connection pool detects when it is run in a development nix shell
and uses this port instead of a production unix socket. This way, redis
tests pass even on computers without redis installed.
Jobs API shall now use redis to store and retrieve jobs. This will make
it possible to add pubsub for jobs updates. For now it uses blocking api
of redis.