title: Grails multi column indexes
body: <p>Can someone explain how to define multi column indexes in Grails? The documentation is at best sparse.</p>
  
  <p>This for example does not seem to work at all:
  <a href="http://grails.org/GORM+Index+definitions" rel="noreferrer">http://grails.org/GORM+Index+definitions</a></p>
  
  <p>I've had some luck with this, but the results seems random at best. Definitions that works in one domain class does not when applied to another (with different names of course). 
  <a href="http://www.grails.org/doc/1.1/guide/single.html#5.5.2.6%20Database%20Indices" rel="noreferrer">http://www.grails.org/doc/1.1/guide/single.html#5.5.2.6%20Database%20Indices</a></p>
  
  <p>Some working examples and explanations would be highly appreciated!  </p>