code: function() {
          var self = this;
          return Q.ninvoke(fs, 'readdir', path.join(this.backend.options.path, this.name))
              .then(function(files) {
                  return Q.all(files.map(function(f) {
                      return self.delete(f);
                  }));
              })
              .then(function() {
                  return true;
              });
      }
docs: Delete all items