* WIP: release footprint in the admin UI
* feat: show the commit ID and the date
* chore: change env optional to empty string
* fix: change the FOREM_BUILD_DATE to RELEASE_FOOTPRINT
* feat: add Not Available as a last option
* test: last deployed time and latest commit id
* feat: update the way we change the env variable!
* fix: we need to set the RELEASE FOOTPRINT so that this clause is not hit - `return path if release_footprint.blank?`
* feat: add a Forem Instance Model
* chore: rename variable
* feat: use the new model that we created
* feat: Update the Forem Instance model to remove Not available from the model method and add it to the view layer
* test: Forem Instance model to return the correct values when present
* feat: use Forem.deployed_at instead of the Application config directly
* chore: remove the initializer
* feat: rename the data keys to reflect what it does
* fix: oops evaluate the var
* refactor: static values that can never change during the lifetime of the app should be constants
* chore: setup the test to have a release footprint before the test gets executed
* chore: remove the methods
* revert to method + cache
* revert to using method
* reset the instance variable
* Replace HEROKU_SLUG_COMMIT with custom footprint (naive)
* Fully set RELEASE_FOOTPRINT with the expectation of setting it before launch
* Change tests
* Fix cache
* Initial work for streaming app shell way of using serviceworkers
* Close in on serviceworker adjustment finalization
* Add docs and loading indicator
* Remove useless code
* Don't run on API
* Update app/javascript/contentDisplayPolicy/hideBlockedContent.js
* Fix small details
* Don't run serviceworker.js code in test env
* Fix JS in serviceworker
* Move private keyword to proper place in async controller
* Change shell_version to HEROKU_SLUG_COMMIT
* Update caching config
* Add test for async_info/shell_version
