Gemfile

gem 'sinatra'

result

~/algo_sinatra $ bundle install; bundle lock; ruby test.rb 
Using rack (1.2.1) 
Using sinatra (1.0) 
Using bundler (1.0.0.rc.6) 
Your bundle is complete! Use `bundle show [gemname]` to see where a bundled gem is installed.
Lock is deprecated. Your bundle is now locked whenever you run `bundle install`.
test.rb:16:in `require': no such file to load -- sinatra/static_assets (LoadError)
	from test.rb:16

test.rb

begin
  # Require the preresolved locked set of gems.
  require File.expand_path('../.bundle/environment', __FILE__)
rescue LoadError
  # Fallback on doing the resolve at runtime.
  require "rubygems"
  require "bundler"

  Bundler.setup
end

# Auto-require all bundled libraries.
Bundler.require

require 'sinatra'
require 'sinatra/static_assets'

test.sh

#!/bin/bash
bundle install; bundle lock; ruby test.rb