ActsAsProvider
==============


Example
=======

	class Author < ActiveRecord::Base
		has_one photo
	end

	class Book < ActiveRecord::Base
		belongs_to 	author
		acts_as_provider do
			add.self
			add.author
			add.author.photo
		end
	end

	book = Book.new
	book.provide ["title", "content"] #=> same as { "title" => book.title, "content" => book.content }
	book.provide ["title", "author_name"] #=> same as { "title" => book.title, "author_name" => book.author.name }
	book.provide ["author_photo_file_type"] #=> same as { "author_photo_file_type" => book.author.photo.file_type }

You can apply this plugin like this:
	
	Request:
	get books/1?fields[]=title&fields[]=content
	
	Controller:
	result = Book.find(params[:id]).provide params[:fields]

TODO
=======
1. improve security to prevent:
	user.provide(["destroy"])  #=>  Dangerous!! will destroy the record
2. support inheritant

3. improve performance with :include