Problems with Rack and Sinatra

I’m trying to use rack to deploy a sinatra application.
So far I have this in my config.ru in the webapp root
require ‘rubygems’
require ‘sinatra’

Sinatra::Application.default_options.merge!(
:run => false,
:env => :production,
:views => ‘/webapps/example’
)

require ‘app.rb’
run Sinatra.application

Now in the sinatra app, it’s simple. I just have this:
get ‘/’ do
‘Hello Sinatra!’
end

When I try to access the website I get this error:
undefined method `default_options’ for Sinatra::Application:Class

I’m pretty new to Ruby so any pointers on where to look would be
helpful.

Thanks in advance.