title: git push difference of branch with master
body: <p>Assume a new local branch named debug and the master is already pushed to the origin. 99% of the debug branch is the same as the master branch.
  when I use <code>git push -u origin debug</code>, it begins to upload the whole about 1 gig project.
  Is it possible instead of uploading the whole 1gig project as a new branch, just upload the changed files and copy(or maybe clone or reuse) the rest files from the master which is already uploaded?</p>