ActiveSession.cleaned_up_lookup_entries to use Redis#pipelined

app/models/active_session.rb

@@ -136,9 +136,11 @@ class ActiveSession
     # only the single key entries are automatically expired by redis, the
     # lookup entries in the set need to be removed manually.
     session_ids_and_entries = session_ids.zip(entries)
+    redis.pipelined do
       session_ids_and_entries.reject { |_session_id, entry| entry }.each do |session_id, _entry|
         redis.srem(lookup_key_name(user.id), session_id)
       end
+    end
 
     entries.compact
   end