Missing license

[smulube]

Hi, there is no license attached to this code, which means it's impossible for us to use this code in our project. Would you be able to add a license to the project? I'd be happy to submit a PR with a license included if you could tell me what license you'd like to use.

[hrieke]

The file crockford.rb's header states that the code is licensed under the same terms as Ruby, but I agree, a standard license file is ideal (& don't forget to update the gemspec too).