The ActiveFacts API is a Ruby DSL for managing constellations of elementary facts. Each fact is either existential (a value or an entity), characteristic (boolean) or binary relational (A rel B). Relational facts are consistently co-referenced, so you can traverse them efficiently in any direction. Each constellation maintains constraints over the fact population.
Gemfile gem 'activefacts-api', '~> 0.9.1'
install gem install activefacts-api -v 0.9.1