title: change-merged gerrit hook
body: <p>I'm trying to make alternative to <strong>post-receive</strong> hook, but may be i something did wrong.
  Does this hook work with push commit to master branch (without /for/ control) through gerrit (i have permission to do push commits)? Official doc doesn't give explanation what "merge" request like.</p>
  
  <p>I placed change-merged script to gerrit/hook/ dir (gerrit is the directory with "bin", "plugins" and other gerrit places) , is it right too?</p>