Add some basic support for Ruby.
Use 2-space indents when working with JSON data from knife.

Chef uses 2 space indentation data when editing nodes, roles, and other
data that can be represented as JSON.
Use bolding for types, keywords, functions, and ruby control keywords.
Merge branch 'use-space-indent-on-knife-files' of https://github.com/jszakmeister/vimfiles
Merge branch 'add-ruby-setup' of https://github.com/jszakmeister/vimfiles