Rails 3 comes with baked in support with bundler.
Using Bundler with Rails 3
Install Rails as you normally would. Use sudo if you would normally use sudo to install gems.
$ gem install rails
We recommend using rvm for dependable Ruby installations, especially if you are switching between different versions of Ruby
Generate a Rails app as usual
$ rails new myapp $ cd myapp
Run the server. Bundler is transparently managing your dependencies!
$ rails server
Add new dependencies to your Gemfile as you need them.
gem 'nokogiri' gem 'geokit'
If you want a dependency to be loaded only in a certain Rails environment, place it in a group named after that Rails environment
group :test do gem 'rspec' gem 'faker' end
After adding a dependency, if it is not yet installed, install it
$ bundle install
This will update all dependencies in your Gemfile to the latest versions that do not conflict with other dependencies
Don't forget that non-Rails commands must be executed with bundle exec
$ bundle exec cucumber
When you're ready to share your application, lock down your dependencies to the specific versions you are using now. This will ensure that other machines use exactly these gems, and are not affected by new releases of gems in the interim
Learn More: bundle lock
$ bundle lock $ git add Gemfile.lock
After locking your dependencies you may not modify the Gemfile without unlocking first
$ bundle unlock
If you've updated your Gemfile and want to install the new gems and re-lock once the new gems are finished installing
$ bundle install --relock