code: function(groupName, resources, callback) {
          var url = this.getResourceUrl({ path: '/groups/' + groupName, user: null });
          request({
              method: 'PUT',
              uri: this.getSignedResourceUrl('PUT', url),
              json: resources,
              onComplete: function(err, res, body) {
                  callback(err, body, res);
              }
          });
  
          return this;
      }
docs: Create/edit a resource group, setting the resources that should be available to it
  
  @param {String} groupName
  @param {Array} resources
  @param {Function} callback
  @return {ImboClient}