title: how do I get the username of the user who started a build in hudson
body: <p>I'm using the groovy post build plugin.</p>
  
  <p><a href="http://wiki.hudson-ci.org/display/HUDSON/Groovy+Postbuild+Plugin" rel="nofollow">http://wiki.hudson-ci.org/display/HUDSON/Groovy+Postbuild+Plugin</a></p>
  
  <p>I'd like to access the username of the user who started the build. What is the correct variable for this?</p>