Create a JSON example (doesn't work yet).
user
```ruby
$LOAD_PATH.unshift(File.join(File.dirname(__FILE__), '..', 'lib'))

require "rubygems"
require "representative/json"
require "ostruct"

books = [
  OpenStruct.new(
    :title => "Sailing for old dogs", 
    :authors => ["Jim Watson"],
    :published => OpenStruct.new(
      :by => "Credulous Print",
      :year => 1994
    )
  ),
  OpenStruct.new(
    :title => "On the horizon", 
    :authors => ["Zoe Primpton", "Stan Ford"],
    :published => OpenStruct.new(
      :by => "McGraw-Hill",
      :year => 2005
    )
  ),
  OpenStruct.new(
    :title => "The Little Blue Book of VHS Programming",
    :authors => ["Henry Nelson"],
    :rating => "****"
  )
]

json = Representative::Json.new do |r|
  r.list_of :books, books do
    r.element :title
    r.list_of :authors
    r.element :published do
      r.element :by
      r.element :year
    end
  end
end

puts json.to_json
```
assistant