Migrating yard documentation to githb-pages

[pitr-ch]

Hi guys,

would you agree If I moved our documentation from http://rubydoc.info/ to github pages for this repository?

reasons:

• I hit an issue which I cannot get around. {include:file:a/path} is not working on rubydoc.info
• We would have more control over the generated documentation (add plugins, update template).

If you agree I'll create a script which will push the generated documentation from doc directory to github pages. I'll do it in #100 PR with the documentation I am putting together there.

[jdantonio]

I'm fine with that. I put the docs in rubydoc.info simply because I didn't know where else to put it.

[pitr-ch]

done in #100, There are 2 new rake tasks: rake yard to generate the doc (just yard also works), and rake yard:push to update gh-pages branch.