Do not generate lib/assets directory for api apps

railties/lib/rails/generators/rails/app/app_generator.rb

@@ -262,6 +262,7 @@ def create_vendor_files
       def delete_app_assets_if_api_option
         if options[:api]
           remove_dir 'app/assets'
+          remove_dir 'lib/assets'
         end
       end
 

railties/test/generators/api_app_generator_test.rb

@@ -62,7 +62,6 @@ def default_files
       db
       lib
       lib/tasks
-      lib/assets
       log
       test/fixtures
       test/controllers
@@ -80,6 +79,7 @@ def skipped_files
        config/initializers/assets.rb
        config/initializers/cookies_serializer.rb
        config/initializers/session_store.rb
+       lib/assets
        vendor/assets
        test/helpers
        tmp/cache/assets)