title: Trigger Jenkins job on GitHub PUSH to specific branch
body: <p>I'm trying to trigger a job based on a GitHub PUSH to a certain branch. </p>
  
  <p>I set up a webhook to <code>JENKINS_URL/git/notifyCommit?url=REPO_URL</code> and <code>Poll SCM</code> without schedule. </p>
  
  <p>The job is being triggered for every <code>push</code> but I cannot filter out the branch - I'd like it to only happen when there's a push to master.</p>