title: Not able to commit/push file permission changes to git
body: <p>I have some files in GIT which have -rwxr-xr-x permissions.</p>
  
  <p>I need to change it to 640 (rw-,r--,---)</p>
  
  <p>I run chmod 640 </p>
  
  <p>But when I run git diff or git commit, these file permission changes are not shown or committed.</p>
  
  <p>How can I perform the above? Please help.</p>