will_paginate query with per_page working in rails3

will_paginate_in_rails3.example.rb

@articles = Article.
  select('articles.*, (SUM(votes.vote = 1)/COUNT(votes.vote)) votes_ratio, COUNT(votes.vote) votes_num').
  joins(:votes).
  group('articles.id').
  having('votes_num >= 5 AND votes_ratio >= 0.8').
  order('votes_ratio DESC, votes_num DESC').
  paginate(:page => params[:page], :per_page => Article.per_page)