Add zero-config self hosting on Render (#612)

* v1 of backend implementation for self hosting

* Add docs

* Add upgrades controller

* Add global helpers for self hosting mode

* Add self host settings controller

* Conditionally show self hosting settings

* Environment and config updates

* Complete upgrade prompting flow

* Update config for forked repo

* Move configuration of github provider within class

* Add upgrades cron

* Update deploy button

* Update guides

* Fix render deployer

* Typo

* Enable auto upgrades

* Fix cron

* Make upgrade modes more clear and consistent

* Trigger new available version

* Fix logic for displaying upgrade prompts

* Finish implementation

* Fix regression

* Trigger new version

* Add i18n translations

* trigger new version

* reduce caching time for testing

* Decrease cache for testing

* trigger upgrade

* trigger upgrade

* Only trigger deploy once

* trigger upgrade

* If target is commit, always upgrade if any upgrade is available

* trigger upgrade

* trigger upgrade

* Test release

* Change back to maybe repo for defaults

* Fix lint errors

* Clearer naming

* Fix relative link

* Add abs path

* Relative link

* Update docs

app/controllers/application_controller.rb

@@ -1,5 +1,5 @@
 class ApplicationController < ActionController::Base
-  include Authentication
+  include Authentication, Invitable, SelfHostable
   include Pagy::Backend
 
   before_action :sync_accounts
@@ -11,11 +11,6 @@ class ApplicationController < ActionController::Base
 
   private
 
-  def hosted_app?
-    ENV["HOSTED"] == "true"
-  end
-  helper_method :hosted_app?
-
   def sync_accounts
     return if Current.user.blank?