title: Extending SonarQube FindBugs plugin with custom FindBugs plugin
body: <p>We created a custom plugin for FindBugs (for clarity: this is a findbugs-plugin, not a sonar-plugin) and we want to extend the FindBugs sonar-plugin with our custom findbugs-plugin.</p>
  
  <p>Currently we use SonarQube 5.1 with the FindBugs sonar-plugin 3.2.</p>
  
  <p>Because our custom findbugs-plugin is a valid plugin for FindBugs, we thought that the most straightforward way to activate it is to use the plugin system of the FindBugs instance from our existing sonar-plugin but we were not able to find how to activate our findbugs-plugin this way.</p>
  
  <p>We also tried to create a rules.xml and place our jar in sonar_home/extensions/rules/findbugs as described in <a href="https://jira.sonarsource.com/browse/SONAR-1481">https://jira.sonarsource.com/browse/SONAR-1481</a> but this does not seem to work with the FindBugs sonar-plugin version we are using.</p>
  
  <p>What is the proper way to configure our version of SonarQube to pick up our custom FindBugs plugin? What steps do we need to take?</p>