title: SonarQube: Create PL/SQL custom rules
body: <p>I'd like to learn how to create custom rules for the SonarQube PL/SQL Plugin, however the link on the official Sonar website is "broken". Clicking on it opens a page with a "The page you are looking for does not exist" error. Does anyone know if it is possible to find documentation on this elsewhere?</p>
  
  <p>I know this might not be the place to ask these types of questions but I don't know where else to ask and maybe someone will know. Thank you.</p>
  
  <p>This is the link about the plugin in, clicking on "custom rules" from the Advanced Usage section leads to the non existent page error.
  <a href="http://docs.sonarqube.org/pages/viewpage.action?pageId=6389850" rel="nofollow">http://docs.sonarqube.org/pages/viewpage.action?pageId=6389850</a></p>