title: Undo removal of file from a previous commit
body: <p>I am using gitflow branching model for development.
  I've branched from <code>develop</code> to <code>feature/X</code> and in the very first commit in <code>feature/X</code> I also deleted some files (using <code>git rm &lt;file&gt;</code>).
  Now after a couple of other commits in that branch I have realized, that I need the files I have deleted earlier.</p>
  
  <p>Here's a short sample to illustrate what i mean for clarification:</p>
  
  <pre><code>git flow init -d
  echo "file contents" &gt; file.txt
  git commit -m "Added file.txt"
  git checkout -b feature/X
  git rm file.txt
  echo "foo" &gt; foo.txt
  git add --all
  git commit -m "Deleted file.txt and added another file"
  &lt;some more commits in feature/X&gt;
  
  
  
  git log -u
  
  ...
  
  commit 04948fc4fc36d83901a0862b057657f3ccb9cf0d
  Author: &lt;...&gt;
  Date:   Wed Aug 10 12:26:58 2016 +0200
  
      Deleted file.txt and added another file
  
  diff --git a/file.txt b/file.txt
  deleted file mode 100644
  index d03e242..0000000
  --- a/file.txt
  +++ /dev/null
  @@ -1 +0,0 @@
  -file contents
  diff --git a/foo.txt b/foo.txt
  new file mode 100644
  index 0000000..257cc56
  --- /dev/null
  +++ b/foo.txt
  @@ -0,0 +1 @@
  +foo
  
  ...
  </code></pre>
  
  <p>I don't just want to re-add the file in a new commit to avoid issues when merging <code>feature/X</code> to <code>develop</code> while there has been some changes in <code>file.txt</code> in <code>develop</code> branch.</p>
  
  <p>Is there any way to take out the removal of <code>file.txt</code> from that earlier commit?</p>
  
  <p>I have tried <code>git reset &lt;sha-of-previous-commit&gt; file.txt</code> but that didn't bring back the file to my working copy.</p>
  
  <p><strong>EDIT 1:</strong><br>
  I know about the down sides of rewriting history that has been pushed to a remote already. However I know nobody has done any commits on <code>feature/X</code> except me hence it should be safe for me to rewrite the history although it has been pushed already.</p>