Sinartra limit blog posts displayed on a page

To limit the number of database elements returned in ActiveRecord is trivial but there is a little bit of work involved with getting the links setup to jump forward and backwards.

I have decided to use these [1,2,3] URLs to navigate the list of blog posts
[1] /blog : always the latest
[2] /blog/older : The next page of blog posts
[3] /blog/older/integer : a page of blog posts starting at integer the links provided will increment this by a fixed amount, but the route can accept any value.

NB: as allways I have inserted some extra space in to the code to get it to display rather than render, you may have to delete spaces after <.

My app.rb:

require 'rubygems'
require 'sinatra'
require 'active_record'

$blogpath = "blog"
$blogs_per_page = 10

ActiveRecord::Base.establish_connection(
  :adapter   => 'sqlite3',
  :database  => './db/blog.db'
)

class Posts < ActiveRecord::Base
end

get '/blog/?' do
   @offset = 0
   @posts  = Posts.find(:all, :order => "id DESC", :limit => $blogs_per_page)
   erb :'blog/all'
end

get '/blog/older/?' do
   #This probably should be a redirect to /blog/older/$blogs_per_page
   @offset = $blogs_per_page
   @posts  = Posts.find(:all, :order => "id DESC", :limit => $blogs_per_page, :offset => @offset)
   erb :'blog/all'
end

get '/blog/older/:offset/?' do
   @offset = params[:offset].to_i
   @posts  = Posts.find(:all, :order => "id DESC", :limit => $blogs_per_page, :offset => @offset)
   erb :'blog/all'
end

The views/blog/all.erb

< %# This section adds control on top  %>
< p>
< a href="/<%=$blogpath%>"> latest <%=$blogpath%>< /a> 

<% if @offset>($blogs_per_page-1) %>
 | < a href="/<%=$blogpath%>/older/<%=@offset-$blogs_per_page%>"> newer <%=$blogpath%>< /a>
<%end%>

 | < a href="/<%=$blogpath%>/older/<%=@offset+$blogs_per_page%>"> older <%=$blogpath%>< /a> 
< /p>

<%# This section lists all the Posts passed to it %>
<% for post in @posts %> 
  < h2>< a href="/<%=$blogpath%>/<%=post.id%>"> <%= post.title %>< /a>< /h2>
  < p><%=post.body%>< /p>
<% end %>