library.rb

# == Schema Information
#
# Table name: libraries
#
#  id           :integer          not null, primary key
#  image        :string(255)
#  file_size    :integer
#  user_id      :integer
#  content_type :string(255)
#  created_at   :datetime         not null
#  updated_at   :datetime         not null
#

class Library < ActiveRecord::Base
  attr_accessible :image, :file_size
  mount_uploader :image, LibraryUploader
  include Rails.application.routes.url_helpers
  belongs_to :user

  before_save :update_asset_attributes
  paginates_per 20

private

  def update_asset_attributes
    if image.present? && image_changed?
      self.content_type = image.file.content_type
      self.file_size = image.file.size
    end
  end
end