fix(Creating Groups): it should be update instead of edit

The code example is not listed any edit action in permissions:

```
permissions: {
  addMember: ['instructor'],
  create: ['instructor'],
  update: ['instructor', 'assistant'],
  participate: ['instructor', 'assistant', 'student'],
  read: ['instructor', 'assistant', 'student', 'anonymous'],
  delete: []
}
```