title: How to trigger Jenkins build on specific branch(release branch) merges to master in Jenkins
body: <p>I am trying to trigger a build on the master branch when a specific branch is merged into it i.e., To trigger a Jenkins pipeline build when a release branch is merged to the master branch.</p>
  
  <p>What I am able to do is if any branch is merged to master, it is triggering the Jenkins build, but what I want is to build to be only triggered on release branch merges into master. For this I used Generic webhook trigger Plugin(GWT). Not sure if I can use Generic webhook trigger for specific branch merge into master.</p>
  
  <p>I tried the following settings in Jenkins pipeline configuration using GWT plugin.
  Optional Filter:
  Expression -  <code>^(refs/heads/master)$</code>
  This expression is working when I merge any branch into Master and triggering the build. But, I want the merge to happen just when a release branch is merged into Master.</p>