Deploy rack applciaton

Make config.ru with following content:

require 'rubygems'
require 'sinatra'
require './my_sinatra_application.rb'

run Sinatra::Application

You have to run bundle command. This will be install all necessary gems that listed in Gemfile.

You find debug log in default apache 2 error log files. This is /var/log/apache2/error.log in my case.