Hisyo is a generator that for your pure Sinatra project to play.

$ gem install hisyo
$ rbenv rehash; rehash; # if necessary
$ hisyo -r ~/myapp
Complete.
  $ cd ~/myapp
  $ rackup (or `rspec spec/`, `vim app/helpers.rb`, etc)
$ cd ~/myapp
$ tree -Fa
.
├── .gitignore
├── Gemfile
├── app/
│   ├── app.rb
│   ├── assets/
│   ├── controllers.rb
│   ├── helpers.rb
│   └── views/
│       └── index.str
├── config/
│   └── boot.rb
├── config.ru
├── db/
├── lib/
├── log/
├── public/
├── spec/
│   ├── hello_spec.rb
│   └── spec_helper.rb
├── tmp/
└── views/

11 directories, 10 files

$ rackup
[2012-05-28 02:24:32] INFO  WEBrick 1.3.1
[2012-05-28 02:24:32] INFO  ruby 1.9.3 (2012-02-16) [x86_64-linux]
[2012-05-28 02:24:32] INFO  WEBrick::HTTPServer#start: pid=11232 port=9292
^C
$ hisyo -r . -k travis
create: ./.travis.yml
create: ./Rakefile

Generated project(as below) is a purely Sinatra application. That means you can gem uninstall hisyo after generation.