Recommendable Versions Save

This release includes a fix for using ActiveRecord UUIDs.

New things:

• Support for UUIDs (config.orm = :active_record_uuid)
• Allow setting a dynamic Redis namespace (config.redis_namespace = -> { … })
• Allow using methods such as liked_for with module-nested models (e.g. current_user.liked_for(Forem::Post))

Fixes:

• Fix a syntax issue with quotes in PostgreSQL

• Recommendations with negative scores, which occurs when there aren't many good ones available, will no longer be returned
• Recommendations are now correctly sorted by score when returned, but no longer return a chainable Relation
• User IDs will be to_s'd upon entering the Enqueue method, to support changes being made in Mongoid 4

• Redis commands used during similarity value/recommendation generation are now Pipelined, greatly improving performance. Thanks to @ajjahn (#90)

• Ratable subclasses behave more sanely, getting their own keys in Redis. This changes the behavior of Recommendable::Ratable.top and shows only items of the requested class (not the entire STI hierarchy)
• Recommendable::Ratable.top can now take an options hash with options[:count] and options[:offset] both supported

• Add an unrate method that will unlike, undislike, or unhide (and unbookmark) the passed object (#81)