Add Sidekiq and Kafka. 

Also:
+ KafkaEvent to publish arbitrary info about models, still kind of a work in progress
+ ClassificationLifecycle management moved to a sidekiq worker
+ MultiKafkaProducer Module to abstract between jruby-kafka and poseidon. 

When running jruby you'll also need to use jbundler to manage Kafka libraries. 
could perhaps save an N+1 if the model has eager loaded the association here, e.g.:
https://github.com/RestPack/restpack_serializer/commit/fd42db838e2a3c9a66a5e13e661dcd11985a0f6a