@Override
	public <S extends T> Iterable<S> save(Iterable<S> entities) {
		for (S entity : entities) {
			save(entity);
		}
		return entities;
	}
Perform bookkeeping of entities managed by this repository. Uses a redis sorted set with a dummy value, which
happens to guarantee that keys for a given score are in sorted order.
spring-xd-analytics/src/main/java/org/springframework/xd/store/AbstractRedisRepository.java