bundler.md

Install the pre-release of bundler. When 1.0 is final the --pre flag will not be necessary.

$ gem install bundler --version=1.0.0.rc.2
Successfully installed bundler-1.0.0.rc.2
1 gem installed

Modify your Gemfile, and locally re-bundle you app with the new bundler options. If bundler complains about the Gemfile format, fix it according to the directions on http://gembundler.com/v1.0/index.html. If you have an old bundler gem defined in your Gemfile, make sure to un-pin it from 0.9.x.

$ echo >> Gemfile
$ bundle install --path vendor/bundle
Fetching source index for http://rubygems.org/
Installing rack (1.2.1) 
Installing sinatra (1.0) 
Using bundler (1.0.0.rc.2) 
Your bundle is complete! Use `bundle show [gemname]` to see where a bundled gem is installed.
Your bundle was installed to `vendor/bundle`

Change how bundler is invoked in your app's bootup and test your application. Sample config.ru:

require 'rubygems'
require 'bundler'
Bundler.setup

require 'sinatra'
require 'web'

run Sinatra::Application

Commit the modified Gemfile and the Gemfile.lock. The Gemfile.lock contains the full list of gem dependencies and helps keep your gems in sync across multiple developers and on Heroku.

$ git add Gemfile Gemfile.lock && git commit -m 'bundler 1.0 Gemfile and lock'
[master 8312d83] bundler 1.0 Gemfile and lock
 2 files changed, 12 insertions(+), 0 deletions(-)
 create mode 100644 Gemfile.lock

$ echo 'vendor/bundle' > .gitignore
$ git add .gitignore && git commit -m 'ignore bundled gems'
[master 1ed0b4a] ignore bundled gems
 1 files changed, 1 insertions(+), 0 deletions(-)
 create mode 100644 .gitignore

Push to Heroku, and compare the Bundler output to your local install. It is important that you push a modified Gemfile ensure that Heroku will re-bundle your application.

$ git push heroku master
Counting objects: 15, done.
Delta compression using up to 2 threads.
Compressing objects: 100% (12/12), done.
Writing objects: 100% (13/13), 1.39 KiB, done.
Total 13 (delta 4), reused 0 (delta 0)

-----> Heroku receiving push
-----> Sinatra app detected
-----> Gemfile detected, running Bundler version 1.0.0.rc.2
       Unresolved dependencies detected; Installing...
       Fetching source index for http://rubygems.org/
       Installing rack (1.2.1) 
       Installing shotgun (0.8) 
       Installing sinatra (1.0) 
       Using bundler (1.0.0.rc.2) 
       Your bundle is complete! Use `bundle show [gemname]` to see where a bundled gem is installed.
       Your bundle was installed to `.bundle/gems`
       Compiled slug size is 260K
-----> Launching..... done
       http://bundler-test.heroku.com deployed to Heroku

To git@heroku.com:bundler-test.git
   9f92823..a15e5be  master -> master

From here on out, when you change your Gemfile, run bundle install and commit the new Gemfile and Gemfile.lock.