title: Updating Jira ticket from jenkins 2 pipeline
body: <p>Hi I am implementing a jenkins 2 pipeline. I am trying to create a groovy function that will update a given story in Jira. I found the below code which I have been told should work.</p>
  
  <pre><code>step([$class: 'hudson.plugins.jira.JiraIssueUpdater', 
  issueSelector: [$class: 'hudson.plugins.jira.selector.DefaultIssueSelector'], 
  scm: [$class: 'GitSCM', branches: [[name: '*/master']], 
      userRemoteConfigs: [[url: 'https://github.com/jglick/simple-maven-project-with-tests.git']]]])
  </code></pre>
  
  <p>I am wondering how is the ticket specified using this? 
  Would anyone be able to describe what is happening in this code?</p>