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. 
safely rescue a missing config file here and degrade the kafka functionality?
ala: https://github.com/zooniverse/Panoptes/blob/cf032a0c3f95a5b7ab1a0035b26a117c1b240a72/config/initializers/airbrake.rb#L9