title: Mahout's datamodel with GenericDataModel
body: <p>I am playing around with Mahout's recommendation engines and are running into problem with using genericdatamodel object.  My question is if I want to add some new users data into the existing datamodel, is the only way to do it, by reconstruction of a new datamodel by reading all the data again.  </p>
  
  <p>Currently, our data is in the cache.</p>