sendMessageToList :: Message -> MailingListId -> Handler ()
sendMessageToList msg listId = runDB $ do
  addrs <- selectList [MailingListUserList ==. listId] []
  lift $ mapM_ (sendMessageToListUser msg listId) addrs
sendMessageToList :: Message -> MailingListId -> Handler ()
sendMessageToList msg listId = runDB $ do
  addrs <- selectList [MailingListUserList ==. listId] []
  lift $ mapM_ (sendMessageToListUser msg listId) addrs
sendMessageToList msg listId = runDB $ do
  addrs <- selectList [MailingListUserList ==. listId] []
  lift $ mapM_ (sendMessageToListUser msg listId) addrs