Add user_preferences_usage to usage ping

lib/gitlab/usage_data.rb

@@ -90,7 +90,10 @@ module Gitlab
             todos: count(Todo),
             uploads: count(Upload),
             web_hooks: count(WebHook)
-          }.merge(services_usage).merge(approximate_counts)
+          }
+          .merge(services_usage)
+          .merge(approximate_counts)
+          .merge(user_preferences: user_preferences_usage)
         }
       end
       # rubocop: enable CodeReuse/ActiveRecord
@@ -159,6 +162,10 @@ module Gitlab
         }
       end
 
+      def user_preferences_usage
+        {} # augmented in EE
+      end
+
       def count(relation, fallback: -1)
         relation.count
       rescue ActiveRecord::StatementInvalid

spec/lib/gitlab/usage_data_spec.rb

@@ -124,6 +124,7 @@ describe Gitlab::UsageData do
         todos
         uploads
         web_hooks
+        user_preferences
       ))
     end