Supportive

Made changes suggested by reviewer and resubmitting for review.
not sure why @document needs to be an instance variable. You can simply call (!) on symbolize keys, then you can use args.fetch(:symbol, default) in order to extract or set instance variables (which should likely be: author, categories, comments, body, publish_date). This would make the code somewhat easier to read, and probably cut down on a ton of lines. Look into the initialization factory pattern in Practical Object Oriented Ruby (Sandy Metz).