Pull gems from github when they are not available locally on the file…

…system.

Gemfile

@@ -6,7 +6,7 @@ source "http://rubygems.org"
   if File.exist?(library_path)
     gem lib, :path => library_path
   else
-    gem lib
+    gem lib, :git => "git://github.com/rspec/#{lib}.git"
   end
 end