paperclip tips ref: http://qiita.com/daisuke-3/items/dbb84a41178c72ff9c3d
class Movie < ActiveRecord::Base
has_attached_file :image, :styles => { :medium => "300x300>", :thumb => "100x100>" }, :default_url => "/images/:style/missing.png"
end
movie = Movie.new
movie.image = File.open('file')
movie.save!