debundle.rb allows you to require gems that are not in your
Gemfile when inspecting
programs that are run with Bundler.
Use at your own risk!
Paste the code of debundle.rb and you are done! A good place would be your
before requiring irbtools.
The code started as a fork of pry-debundle. There is a longer, more compatible - but not supported - version available in the compat branch.