Replace `serve_static_files` mentions in docs.

Should use `public_file_server.enabled` instead.

Clarified that static files will be served from the public directory, where it made sense.

Also removed occurrence of the deprecated `static_cache_control`.

1 files changed, 4 insertions, 2 deletions

diff --git a/guides/source/upgrading_ruby_on_rails.md b/guides/source/upgrading_ruby_on_rails.md
index 1fe95c3422..fa6a01671b 100644
--- a/guides/source/upgrading_ruby_on_rails.md
+++ b/guides/source/upgrading_ruby_on_rails.md
@@ -1191,8 +1191,10 @@ You can help test performance with these additions to your test environment:
 
 ```ruby
 # Configure static asset server for tests with Cache-Control for performance
-config.serve_static_files = true
-config.static_cache_control = 'public, max-age=3600'
+config.public_file_server.enabled = true
+config.public_file_server.headers = {
+  'Cache-Control' => 'public, max-age=3600'
+}
 ```
 
 ### config/initializers/wrap_parameters.rb