Allow models to load when the database is offline

It used to be necessary to stop ActiveRecord loading because
it would immediately try and connect the database but with the
introduction of switchable database connections it now only connects
when a model is used for the first time.

Fixes openstreetmap#3858

config/application.rb

@@ -1,18 +1,6 @@
 require_relative "boot"
 
-if ENV.fetch("OPENSTREETMAP_STATUS", nil) == "database_offline"
-  require "active_model/railtie"
-  require "active_job/railtie"
-  require "active_storage/engine"
-  require "action_controller/railtie"
-  require "action_mailer/railtie"
-  require "action_view/railtie"
-  require "action_cable/engine"
-  require "sprockets/railtie"
-  require "rails/test_unit/railtie"
-else
-  require "rails/all"
-end
+require "rails/all"
 
 # Require the gems listed in Gemfile, including any gems
 # you've limited to :test, :development, or :production.
@@ -40,9 +28,6 @@ class Application < Rails::Application
     # like if you have constraints or database-specific column types
     config.active_record.schema_format = :sql unless Settings.status == "database_offline"
 
-    # Don't eager load models when the database is offline
-    config.paths["app/models"].skip_eager_load! if Settings.status == "database_offline"
-
     # Use memcached for caching if required
     config.cache_store = :mem_cache_store, Settings.memcache_servers, { :namespace => "rails:cache" } if Settings.key?(:memcache_servers)