title: .npmrc file permission are not stored by git
body: <p>In my project I want to use a <code>.npmrc</code> file to point to a private repository. From the documentation for npmrc we read:</p>
  
  <blockquote>
    <p><strong>NOTE:</strong> Because local (per-project or per-user) <code>.npmrc</code> files can contain sensitive credentials, they must be readable and writable only by your user account (i.e. must have a mode of <strong>0600</strong>), <em>otherwise they will be ignored by npm</em>!</p>
  </blockquote>
  
  <p>unfortunately git is not honouring the file permission 0600.</p>
  
  <p>So: how to store the <code>.npmrc</code> file in git?</p>