How to use gems not in a Gemfile when working with bundler?

Question

When using bundler with a project in general and Rails specifically, you have access only to gems defined in your Gemfile. While this makes sense, it can be limiting. Mostly

Answer 1

In case you still decide to do this (horrible idea):

You can add ruby code to your Gemfile to load a ~/.gemfile (or such) if it exists.

Something like:

eval(IO.read('~/.gemfile'), binding) if FileTest.exists?("~/.gemfile")