docs: function purgeResource(resource, archive) {
          if (!resource.purge) { return true; }
  
          var criteria = resource.purge();
          var deferred = Q.defer();
  
          archive.bind(resource.name);
          archive[resource.name].remove(criteria, function (err, results) {
              err ? deferred.reject(err) : deferred.resolve(results);
          });
          return deferred.promise;
      }