def merge(user, light_user):
        entries = UserHistoryLog.objects.filter(user=None,
                                                light_user=light_user)
        if entries.count() > 0:
            with log.fields(username=user.username,
                            num_entries=entries.count(),
                            light_user=light_user):
                log.info('Merging user history logs')
                entries.update(user=user)