title: Get All Revisions for a specific file in gitpython
body: <p>I am using <a href="https://pypi.python.org/pypi/GitPython/" rel="noreferrer">gitpython</a> library for performing git operations, retrieve git info from python code. I want to retrieve all revisions for a specific file. But couldn't find a specific reference for this on the <a href="http://gitpython.readthedocs.org" rel="noreferrer">docs</a>. </p>
  
  <p>Can anybody give some clue on which function will help in this regard? Thanks.</p>