title: git create commit from diff between two branches
body: <p>I have two branches which have very little similar history, but are related to each other.</p>
  
  <p>I want the changes between those two in <strong>one</strong> git commit.</p>
  
  <p>files have been deleted and created between those patches and I want the patch to reflect that</p>
  
  <p>i.e.: the following stuff will not work:</p>
  
  <pre><code>git diff branch_a branch_b -- &gt; patchfile
  git checkout branch_b
  git apply patchfile # deletes and adds are ignored
  git commit # we miss the deletes
  </code></pre>