Why can't bundler locate the Mechanize gem?
The following is in my Rails project's Gemfile:
gem 'mechanize', :git => 'git://github.com/tenderlove/mechanize.git'
Fetching source index for http://rubygems.org/
Could not find gem 'mechanize (>= 0)' in git://github.com/tenderlove/mechanize.git (at master).
Source does not contain any versions of 'mechanize (>= 0)'
It looks as though the project is missing a gemspec and one won't be getting added.
You should be able to clone the project into your vendor/gems directory. You will need to create a mechanize.gemspec file, too. You would then require it in your Gemfile using something like.
gem 'mechanize', :path => 'vendor/gems/mechanize'