title: GitLab merge behavior - keep file from branch
body: <p>Is it possible to default to one branche's version of a file when doing merge requests in GitLab Web Interface?</p>
  
  <p>I'm trying to set up the GitLab Web Interface, so that you can use the graphical interface to do merge requests. In these merge requests, certain files on the target branch must not be subject to any changes.</p>
  
  <p>Most often, I'm working on web projects with a config.php, and here we can see how it's possible to not overwrite the config in branch 'prod' with anything (ie from 'dev') </p>
  
  <p><a href="https://stackoverflow.com/questions/5465122/gitattributes-individual-merge-strategy-for-a-file">.gitattributes &amp; individual merge strategy for a file</a></p>
  
  <p>I tried to apply this to our server by doing</p>
  
  <pre><code>    # In my local repo
      git checkout production
      echo "config.php merge=ours" &gt;&gt; .gitattributes
      git add -A &amp;&amp; git commit -am 'Add gitattributes'
      git push origin production
  
      git checkout -b dev
      rm .gitattributes
      echo "OneMoreLine" &gt;&gt; config.php
      git add -A &amp;&amp; git commit -am 'Delete gitattributes, alter config'
      git push origin dev
  
      # SSH on the GitLab Server
      sudo git configure --global merge.ours.name "Keep OUR version"
      sudo git configure --global merge.ours.driver true
  
      # GitLab Web Interface /group/repo/tree/dev
      Create MR
      From dev into production
  </code></pre>
  
  <p>I expected the "OneMoreLine" to be missing in <code>production</code>, but GitLab seems to be unaffected by the .gitattributes and config.</p>
  
  <p>Can we somehow configure GitLab to achieve this? Perhaps with a non-global or other user's config?</p>