Song Model

gistfile1.rb

class Song < ActiveRecord::Base
  belongs_to :user

  acts_as_voteable
  
  has_attached_file :music, :storage => :s3, :s3_credentials => "#{Rails.root}/config/s3.yml"

  validates_attachment_content_type :music, :content_type => ['application/mp3', 'application/x-mp3', 'audio/mpeg', 'audio/mp3' ],
                                    :message => 'file must be of filetype .mp3!'

  validates_attachment_size :music, :less_than => 10.megabytes

  def previous_song
    self.class.first(:conditions => ["created_at < ?", created_at], :order => "created_at desc")
  end

  def next_song
    self.class.first(:conditions => ["created_at > ?", created_at], :order => "created_at asc")
  end

end