meta_where

https://github.com/ernie/meta_where

MetaWhere offers the ability to call any Arel predicate methods (with a few convenient aliases) on your Model's attributes instead of the ones normally offered by ActiveRecord's hash parameters. It also adds convenient syntax for order clauses, smarter mapping of nested hash conditions, and a debug_sql method to see the real SQL your code is generating without running it against the database. If you like the new AR 3.0 query interface, you'll love it with MetaWhere.