Support building gem and doc locally

Since in windows, commit message requires double quote, otherwise, it will throw error.

I'm wondering if it's suggested to build latest cucumber gem locally.
There's no direct way to build gem file locally. So add it.
Please let me know if it's not a good approach.

BTW, I'm thinking where to add 'rake build'. Should it be added in readme or configure file?
Could you kindly give a suggestion.

Thanks!