title: Git - pull file only if not already present
body: <p>I have a project in my repo and it contains 3 sqlite database files. When I pull the repo on a pc, I need to download those files to in order for the program to work.</p>
  <p>But once the files are present locally, I do not want to overwrite them on new pulls. Is there a way to ignore those files only if they already exist? And is there a simple way to force the pull anyway in case of big structural changes?</p>