relix

https://github.com/ntalbott/relix

Relix is a layer that can be added on to any model to make all the normal types of querying you want to do: equality, less than/greater than, in set, range, limit, etc., quick and painless. Relix depends on Redis to be awesome at what it does - blazingly fast operations on basic data types - and layers on top of that pluggable indexing of your data for fast lookup.