* 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
The `.env` file shouldn't live in the `/config` directory when it is created, but
currently, the `.env_sample` file lives within `/config`. This can be confusing and
cause ENV var issues if someone duplicates `.env_sample` and renames it to `.env`,
because none of their ENV variables will get picked up, since their `.env` file will
mistakenly end up in `/config`.
This change moves `.env_sample` out of `/config`, and updates the documentation/relevant
.yml files accordingly.
