[Doc] Sync the Rails configuration tip with the README

Author: koic

docs/modules/ROOT/pages/usage.adoc

@@ -33,18 +33,17 @@ end
 
 == Rails configuration tip
 
-If you are using Rails 6.1 or newer, add the following `config.generators.after_generate` setting to
-your config/application.rb to apply RuboCop autocorrection to code generated by `bin/rails g`.
+In Rails 6.1+, add the following `config.generators.after_generate` setting to
+your `config/environments/development.rb` to apply RuboCop autocorrection to code generated by `bin/rails g`.
 
 [source,ruby]
 ----
-module YourCoolApp
-  class Application < Rails::Application
-    config.generators.after_generate do |files|
-      parsable_files = files.filter { |file| File.exist?(file) && file.end_with?('.rb') }
-      unless parsable_files.empty?
-        system("bundle exec rubocop -A --fail-level=E #{parsable_files.shelljoin}", exception: true)
-      end
+# config/environments/development.rb
+Rails.application.configure do
+  config.generators.after_generate do |files|
+    parsable_files = files.filter { |file| file.end_with?('.rb') }
+    unless parsable_files.empty?
+      system("bundle exec rubocop -A --fail-level=E #{parsable_files.shelljoin}", exception: true)
     end
   end
 end
@@ -53,3 +52,18 @@ end
 It uses `rubocop -A` to apply `Style/FrozenStringLiteralComment` and other unsafe autocorrection cops.
 `rubocop -A` is unsafe autocorrection, but code generated by default is simple and less likely to
 be incompatible with `rubocop -A`. If you have problems you can replace it with `rubocop -a` instead.
+
+In Rails 7.2+, it is recommended to use `config.generators.apply_rubocop_autocorrect_after_generate!` instead of the above setting:
+
+[source,diff]
+----
+ # config/environments/development.rb
+ Rails.application.configure do
+   (snip)
+   # Apply autocorrection by RuboCop to files generated by `bin/rails generate`.
+-  # config.generators.apply_rubocop_autocorrect_after_generate!
++  config.generators.apply_rubocop_autocorrect_after_generate!
+ end
+----
+
+You only need to uncomment.