Found this:
The configuration option config.serve_static_assets
has been renamed to config.serve_static_files
to clarify its role.
in config/environments/production.rb
:
# Disable serving static files from the `/public` folder by default since
# Apache or NGINX already handles this.
config.serve_static_files = ENV['RAILS_SERVE_STATIC_FILES'].present?
So set env RAILS_SERVE_STATIC_FILES
or using Nginx
to serving static files.
Add config.serve_static_assets = true
will still work, but removed in future.