The Hashery is a tight collection of Hash-like classes. Included among its many
offerings are the auto-sorting Dictionary class, the efficient LRUHash, the
flexible OpenHash and the convenient KeyHash. Nearly every class is a subclass
of the CRUDHash which defines a CRUD model on top of Ruby's standard Hash
making it a snap to subclass and augment to fit any specific use case.

WWW: http://rubyworks.github.io/hashery/