app/models/post.rb

class Post < ActiveRecord::Base  ...  def post(position)    increment = position == :previous ? -1 : 1    Post.find_by_sequence(self.sequence + increment)  endend

app/helpers/post_helpers.rb

module PostsHelper  def post_link(position)    link_to("#{position.to_s.capitalize} Post", post_url(@post.post(position).sequence)) if @post.post(position)  endend

app/views/posts/show.html.haml

- title "\##{@post.sequence} #{@post.title}"...-# edited 12/19/10.postNav  .prev= post_link(:previous)  .next= post_link(:next)%br%br%p= link_to 'View All Posts', posts_path...