Use implicit dotenv load (#30121)

config/application.rb

@@ -51,12 +51,8 @@ require_relative '../lib/active_record/database_tasks_extensions'
 require_relative '../lib/active_record/batches'
 require_relative '../lib/simple_navigation/item_extensions'
 
-Dotenv::Rails.load
-
 Bundler.require(:pam_authentication) if ENV['PAM_ENABLED'] == 'true'
 
-require_relative '../lib/mastodon/redis_config'
-
 module Mastodon
   class Application < Rails::Application
     # Initialize configuration defaults for originally generated Rails version.
@@ -98,6 +94,10 @@ module Mastodon
       app.deprecators[:mastodon] = ActiveSupport::Deprecation.new('4.3', 'mastodon/mastodon')
     end
 
+    config.before_configuration do
+      require 'mastodon/redis_config'
+    end
+
     config.to_prepare do
       Doorkeeper::AuthorizationsController.layout 'modal'
       Doorkeeper::AuthorizedApplicationsController.layout 'admin'