* Introduce background workers and persistence for analysis results.
* Introduce Redis dependency.
* Add Sidekiq workers and admin UI. Lock down the admin UI with HTTP basic and a configurable password.
* Remove page caching.
* Move helper tests into a subdirectory of the unit tests.

For details on using Sidekiq, see:
http://railscasts.com/episodes/366-sidekiq?view=asciicast