need some clarification on the basic example #46

ac.grant('user') // define new or modify existing role. also takes an array.
  .createOwn('video') // equivalent to .createOwn('video', ['*'])
  .deleteOwn('video')
  .readAny('video')
  .grant('admin') // switch to another role without breaking the chain
  .extend('user') // inherit role capabilities. also takes an array
  .updateAny('video', ['title']) // explicitly defined attributes
  .deleteAny('video');