v 0.2.0
  - '<<' method for quick pack add  w/o specifing namespace
      Ex. Six.new << BookRules.new
  - allowed? method can accept array of actions and return true only if all granted
      Ex. allowed?(:author, [:read, :write, :publish], :book ) # true
      Ex. allowed?(:author, [:read, :write, :publish, :admin], :book ) # false

v 0.1.3
  - initialization with pack as args 
      Ex. Six.new(:book => BookRules.new)
  - initialization with multiple packs
      Ex. Six.new(:book => BookRules.new, :author => AuthorRules.new)

v 0.1.2
  - allowed?(action, object, subject) -> allowed?(object, action, subject)
  - use & use! are now aliases for use_pack & use_pack!

v 0.1.1
  - 'add' - alias method for add_pack
  - 'add!' - alias method for add_pack!
  - 'remove' - alias method for remove_pack
  - 'remove!' - alias method for remove_pack!
  - 'reset' - alias method for reset_use
  - 'exist?' - alias method for pack_exist?
  - attr_accessor -> attr_reader for current_rule_pack, rules_packs
