Merge pull request #24709 from y-yagi/add_channels_files_in_stats_task

add channels files in `stats` task

railties/lib/rails/tasks/statistics.rake

@@ -7,6 +7,7 @@ STATS_DIRECTORIES = [
   %w(Jobs               app/jobs),
   %w(Models             app/models),
   %w(Mailers            app/mailers),
+  %w(Channels           app/channels),
   %w(Javascripts        app/assets/javascripts),
   %w(Libraries          lib/),
   %w(Tasks              lib/tasks),