Private data not returning

When making a call to get the authenticated user's gists, it only returns the public gists.

```
import GitHubAPI from 'github-api';

const getGists = (async () => {
var gh = new GitHubAPI({
token: 'token'
});
var user = gh.getUser();
var gists = user.listGists().then( data => data );

return gists;
})
```

Is this a GitHub API issue, a GitHub.JS issue, or am I missing something?