code: function deleteGroup(name, done) {
    return getGroup(name, function(getGroupErr, group) {
      if (getGroupErr) {
        return done(getGroupErr);
      }
  
      if (!group) {
        return done(new Error(`group '${name}' not found`));
      }
  
      return group.destroy(done);
    });
  }
docs: Delete a group
  
  @param {String} name
  @param {Function} done - done(err)