$ sudo gem install google-appengine -V
$ mkdir hello && cd hello
$ appcfg.rb gem install sinatra -V
$ cat > config.ru <<EOF
require 'appengine-rack'
require 'hello'
AppEngine::Rack.configure_app(
  :application => 'your-app-id', 
  :version => 1)
run Sinatra::Application
EOF
$ cat > hello.rb <<EOF
require 'rubygems'
require 'sinatra'
get '/' do "Hello GAE!! #{Time.now}" end
EOF
$ appcfg.rb update .