Merge branch '34891-follow-up-feature-group' into 'master'

Re-add Feature.register_feature_groups which is already documented

Closes #34891

See merge request !12751

config/initializers/flipper.rb

@@ -3,4 +3,6 @@ require 'flipper/middleware/memoizer'
 unless Rails.env.test?
   Rails.application.config.middleware.use Flipper::Middleware::Memoizer,
     lambda { Feature.flipper }
+
+  Feature.register_feature_groups
 end

lib/feature.rb

@@ -57,5 +57,11 @@ class Feature
         Flipper.new(adapter)
       end
     end
+
+    # This method is called from config/initializers/flipper.rb and can be used
+    # to register Flipper groups.
+    # See https://docs.gitlab.com/ee/development/feature_flags.html#feature-groups
+    def register_feature_groups
+    end
   end
 end