[chef] How to push to upstream cookbook-vendor branch?

[Bryan Berry < >]

I am trying to figure out how to "vendor branch" technique to push my changes upstream cookbook. 

Here is the workflow that I have in mind

$ knife cookbook site install <cookbook>

$ vim cookbooks/<cookbook>  #make changes

$ git checkout <cookbook>-vendor  

$ git checkout master path/to/modified-cookbook 

$ git commit -am 'merging select files into vendor-branch'

However, when I  do  $ git checkout chef-<cookbook>-vendor && git ls-files

git seems to be tracking everything in this branch, not just the files for the cookbook. 

I have read through http://wiki.opscode.com/display/chef/Working+with+Git+and+Cookbooks, but it still isn't clear to me how to push my changes to the upstream cookbook. Perhaps I am missing something completely obvious. Can someone enlighten me?

The only other alternative I see is to track down the source of cookbook, fork it, create a patch from my code, apply it to my fork, send a pull request.