Problem deploying my sinatra app

app.rb

require 'rubygems'
require 'sinatra'

unless Kernel.respond_to?(:require_relative)
  module Kernel
    def require_relative(path)
      require File.join(File.dirname(caller[0]), path.to_str)
    end
  end
end

require_relative 'config'
require_relative 'routes'

config.ru

require 'rubygems'
require 'bundler'
Bundler.setup
require './app'
run Sinatra::Application

Gemfile

source 'http://rubygems.org'
gem 'heroku'
gem 'sinatra'

log

2012-08-07T01:19:46+00:00 app[web.1]: /app/config.rb:1:in `require': no such file to load -- sequel (LoadError)
2012-08-07T01:19:46+00:00 app[web.1]: 	from /app/app.rb:16:in `require_relative'
2012-08-07T01:19:46+00:00 app[web.1]: 	from /app/config.ru:5:in `require'
2012-08-07T01:19:46+00:00 app[web.1]: 	from /app/config.ru:5:in `block in <main>'
2012-08-07T01:19:46+00:00 app[web.1]: 	from /app/vendor/bundle/ruby/1.9.1/gems/rack-1.4.1/lib/rack/builder.rb:51:in `initialize'
2012-08-07T01:19:46+00:00 app[web.1]: 	from /app/app.rb:16:in `<top (required)>'
2012-08-07T01:19:46+00:00 app[web.1]: 	from /app/vendor/bundle/ruby/1.9.1/gems/rack-1.4.1/lib/rack/builder.rb:51:in `instance_eval'
2012-08-07T01:19:46+00:00 app[web.1]: 	from /app/config.rb:1:in `<top (required)>'
2012-08-07T01:19:46+00:00 app[web.1]: 	from /app/vendor/bundle/ruby/1.9.1/gems/rack-1.4.1/lib/rack/builder.rb:40:in `eval'
2012-08-07T01:19:46+00:00 app[web.1]: 	from /app/config.ru:1:in `new'
2012-08-07T01:19:46+00:00 app[web.1]: 	from /app/vendor/bundle/ruby/1.9.1/gems/rack-1.4.1/lib/rack/server.rb:200:in `app'
2012-08-07T01:19:46+00:00 app[web.1]: 	from /app/vendor/bundle/ruby/1.9.1/gems/rack-1.4.1/lib/rack/builder.rb:40:in `parse_file'
2012-08-07T01:19:46+00:00 app[web.1]: 	from /app/vendor/bundle/ruby/1.9.1/gems/rack-1.4.1/lib/rack/server.rb:301:in `wrapped_app'
2012-08-07T01:19:46+00:00 app[web.1]: 	from /app/config.ru:1:in `<main>'
2012-08-07T01:19:46+00:00 app[web.1]: 	from /app/vendor/bundle/ruby/1.9.1/bin/rackup:19:in `<main>'
2012-08-07T01:19:46+00:00 app[web.1]: 	from /app/vendor/bundle/ruby/1.9.1/bin/rackup:19:in `load'
2012-08-07T01:19:46+00:00 app[web.1]: 	from /app/vendor/bundle/ruby/1.9.1/gems/rack-1.4.1/bin/rackup:4:in `<top (required)>'
2012-08-07T01:19:46+00:00 app[web.1]: 	from /app/vendor/bundle/ruby/1.9.1/gems/rack-1.4.1/lib/rack/server.rb:252:in `start'
2012-08-07T01:19:46+00:00 app[web.1]: 	from /app/vendor/bundle/ruby/1.9.1/gems/rack-1.4.1/lib/rack/server.rb:137:in `start'
2012-08-07T01:19:46+00:00 heroku[web.1]: Process exited with status 1