skinny 1.3.4 (new formula)

This is new formula proposal. Skinny Framework is a famous web framework in Scala.
http://skinny-framework.org/
We already supports homebrew installation from our alternative repository for months past.
https://github.com/skinny-framework/homebrew-alt

Thank you in advance.
When installing without `-g`, `yo` command won't be created by npm installation. We should create yo command (symbolic link) by hand. Is it really better?