title: Git - how to block merging from master into another branch
body: <p>As <code>.gitignore</code> doesn't work per branch and I need to keep a file in <code>master</code> that shouldn't be in other branches, I wish to block any merging of <code>master</code> into other branches.</p>
  
  <p>I am expecting some <code>.git*</code> like file which I can set in the repository itself that a merge of master into another branch would be rejected or at least a warning would appear.</p>
  
  <p>Is there anyone knows if that is possible anyhow?</p>