title: Add more PR status check (Jenkins blue ocean, integrated with github)
body: <p>I was installing Jenkins (with blue ocean plugin) and successfully configure GitHub webhook, so that, every push to the repository will be checked whether the build process succeeds or not (like this attached image).</p>
  
  <p><a href="https://i.stack.imgur.com/dW9Ey.png" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/dW9Ey.png" alt=""></a></p>
  
  <p>After installing there are 2 status checks that installed by default</p>
  
  <ul>
  <li>jenkins/branch: check if commit could be built successfully and report status back to GitHub</li>
  <li>jenkins/pr-merge: check if PR could be merged with the base branch (currently develop) and report status back to GitHub</li>
  </ul>
  
  <p>I want to <strong>add 1 more status check, like Jenkins/unit-test</strong>. How could I do that from Jenkins side? And where are the 2 status checks mentioned above defined in Jenkins with blue ocean plugin?</p>
  
  <p>The reason I want to add more status check is that I can configure this check as optional, so even unit test failed, I can still merge the pull request.
  (Our project is still in very early development stages, then it is not necessary to require all unit test to pass to merge a PR at the moment.)</p>