gistfile1.txt

class Asset
  include DataMapper::Resource

  property :id,           Integer,  :serial => true
  property :user_id,      Integer,  :nullable => false, :index => true
  property :title,        String
  property :filename,     String
  property :content_type, String
  property :size,         Integer
  property :created_at,   DateTime
  property :updated_at,   DateTime
  property :type,         Discriminator
  
  belongs_to :user

end

class Photo < Asset

  run_later do
    # Rmagick commands
  end

end