$ gem install classifier-reborn
$ irb
irb(main):001:0> require 'classifier-reborn'
irb(main):002:0> classifier = ClassifierReborn::Bayes.new 'Ham', 'Spam'
irb(main):003:0> classifier.train "Ham", "Sunday is a holiday. Say no to work on Sunday!"
irb(main):004:0> classifier.train "Spam", "You are the lucky winner! Claim your holiday prize."
irb(main):005:0> classifier.classify "What's the plan for Sunday?"
#=> "Ham"

irb(main):006:0> lsi = ClassifierReborn::LSI.new
irb(main):007:0> lsi.add_item "This text deals with dogs. Dogs.", :dog
irb(main):008:0> lsi.add_item "This text involves dogs too. Dogs!", :dog
irb(main):009:0> lsi.add_item "This text revolves around cats. Cats.", :cat
irb(main):010:0> lsi.add_item "This text also involves cats. Cats!", :cat
irb(main):011:0> lsi.add_item "This text involves birds. Birds.", :bird
irb(main):012:0> lsi.classify "This text is about dogs!"
#=> :dog
irb(main):013:0> lsi.find_related("This text is around cats!", 2)
#=> ["This text revolves around cats. Cats.", "This text also involves cats. Cats!"]