has_many :comments, -> { left_joins(:author).where(:visible => true, :users => { :status => [nil, "active", "confirmed"] }).order(:created_at) }, :class_name => "NoteComment", :foreign_key => :note_id
has_many :all_comments, -> { left_joins(:author).order(:created_at) }, :class_name => "NoteComment", :foreign_key => :note_id, :inverse_of => :note
+ has_many :subscriptions, :class_name => "NoteSubscription"
+ has_many :subscribers, :through => :subscriptions, :source => :user
validates :id, :uniqueness => true, :presence => { :on => :update },
:numericality => { :on => :update, :only_integer => true }