gistfile1.txt

class Widget < ActiveRecord::Base

  belongs_to :box
  
  has_many :categorizations
  has_many :categories, :through => :categorizations
  
  # Returns a sentence of all the categories.
  def category_names
    if categories.empty?
      "None"
    else 
      categories.map {|c| c.name }.to_sentence
    end
  end
  
end