Just so I'm clear on the logic:
* Say I run bundle package Foo which requires Bar 1.0. Foo 1.0 is now installed in my .rbundle directory.
* I make some changes to Foo which require an upgrade to Bar. I change the description file to require Bar 2.0.
* I bundle Foo again. This should throw and exception because I require Bar 2.0, but have Bar 1.0 already installed.
* Solving this requires killing the .rbundle directory and rebundling?