A minimal Sinatra app deployable to Heroku.

config.ru

require './myapp.rb'
run Sinatra::Application

Gemfile

source :rubygems

gem "sinatra"

Gemfile.lock

GEM
  remote: http://rubygems.org/
  specs:
    rack (1.4.1)
    rack-protection (1.2.0)
      rack
    sinatra (1.3.2)
      rack (~> 1.3, >= 1.3.6)
      rack-protection (~> 1.2)
      tilt (~> 1.3, >= 1.3.3)
    tilt (1.3.3)

PLATFORMS
  ruby

DEPENDENCIES
  sinatra

myapp.rb

require 'sinatra'

get '/' do
  'Hello World!'
end