Untitled

## Campaign.rb
class Campaign < ActiveRecord::Base

  #relationships
  has_one :banner, :class_name => "CampaignPicture", :as => :picturable, :dependent => :destroy
  has_one :mail_banner, :class_name => "CampaignPicture", :as => :picturable, :dependent => :destroy

  accepts_nested_attributes_for :banner,  :reject_if => Proc.new {|attributes| attributes["data"].blank?}
  accepts_nested_attributes_for :mail_banner, :reject_if => Proc.new {|attributes| attributes["data"].blank?}

end

## Picture.rb

class Picture < ActiveRecord::Base
  #acts_as_list :scope => :product

  belongs_to :author, :class_name => 'User', :foreign_key => 'author_id'
  belongs_to :picturable, :polymorphic => true

  #validates_presence_of :content_type, :name, :width, :height

  has_attached_file .....
end

## schema picture table

 create_table "pictures", :force => true do |t|
    t.integer  "author_id"
    t.integer  "last_updater_id"
    t.integer  "position",          :default => 1, :null => false
    t.datetime "created_at"
    t.datetime "updated_at"
    t.integer  "picturable_id"
    t.string   "data_file_name"
    t.string   "data_content_type"
    t.integer  "data_file_size"
    t.datetime "data_updated_at"
    t.string   "picturable_type"
  end