Adding create_ruby_block matcher

The official docs[1] say that the only supported action is create. The code[2] says both :create, and :run are allowed.

[1] http://docs.opscode.com/resource_ruby_block.html#actions
[2]  https://github.com/opscode/chef/blob/62e4f1f1f983029f3565a59d42409312eda17d5a/lib/chef/resource/ruby_block.rb#L30