Fix link to Thor docs [ci-skip]

Author: jonathanhefner

guides/source/rails_application_templates.md

@@ -272,7 +272,7 @@ Advanced Usage
 
 The application template is evaluated in the context of a
 `Rails::Generators::AppGenerator` instance. It uses the
-[`apply`](https://rdoc.info/github/wycats/thor/Thor/Actions#apply-instance_method)
+[`apply`](https://www.rubydoc.info/gems/thor/Thor/Actions#apply-instance_method)
 action provided by Thor.
 
 This means you can extend and change the instance to match your needs.