* set sidekiq session to be the same as Rails to prevent forbidden UI errors
* monkey patch rack until new version is released to make Sidekiq Admin work
* Introduce Sidekiq to the app and update RateLimitCheckerJob to use it
* fix rate limit checker spec with new sidekiq syntax
* add Sidekiq to tech stack overview
* Remove RateLimitChecker job change, add sidekiq web UI and testing support