gist:838448

class NotificationCluster < ActiveRecord::Base
  CLUSTER_TIMEOUT = 30.seconds
  serialize :associated_files			# an array of file ids

  scope :unsent, :conditions => {:delivered => false}
  scope :within_the_last, lambda {|secs|
    {:conditions => ["created_at >= ?", secs.ago]}
  }

  scope :for, lambda{|arguments|