title: How to add String parameter to Jenkins with optional checkbox
body: <p>I'm trying to add a String parameter to my jenkins build, but i can't find an option to make it optional, on the Jenkins WIKI i found a screeshot and there was an option to make it optional: <a href="https://wiki.jenkins-ci.org/display/JENKINS/Parameterized+Build" rel="noreferrer">https://wiki.jenkins-ci.org/display/JENKINS/Parameterized+Build</a> .</p>