* Only bust_fastly_cache if fastly is enabled
* Conditionally bust nginx cache from CacheBuster#bust
* Don't _actually_ call out to openresty
* Remove redundant check for FASTLY_API_KEY in CacheBuster
* Clean up and add a spec
* Do not call .purge_ methods if fastly is not configured
* Add OPENRESTY_ ENV vars to .env_sample
* Remove extra / prepending path
* Remove ConfigurationError, clean up Purgeable concern
* Use raise instead of fail like fastly-ruby
* No longer check for Rails.env.production?
* Use let! to create article in BustMultipleCachesWorker spec
* Add comment referencing Fastly gem
* Create purgable concern and include it
* Typo: deprecate --> deprecated
* Include Purgable on the Tag model
* Rename Purgable to Purgeable
* Reorganize fastly and service methods in Purgeable
* Add and fix specs
* Add development env guards
