coder.rb

class Coder < ActiveRecord::Base
  
  after_save :clear_caches
  
private

  def clear_caches
    Stats.expire_coder_punten
  end
  
end

stats.rb

class Stats

  def punten
    coder_punten + issue_punten
  end

  def expire_coder_punten
    Rails.cache.delete('stats', 'coder_punten')
  end
  
  def expire_issue_punten
    Rails.cache.delete('stats', 'issue_punten')
  end
  
  def coder_punten
    Rails.cache.fetch('stats', 'coder_punten') { Coder.sum(:punten) }
  end
  
  def issue_punten
    Rails.cache.fetch('stats', 'issue_punten') { Issue.sum(:punten) }
  end
  
  class << self
    def method_missing(name, *args, &block)
      self.new.send(name, *args, &block)
    end
  end
end