For API calls that require nested params (eg: http://api.challonge.com/v1/documents/tournaments/create) properties should be specified nested. example:
```
var challonge = require('./node-challonge');
var client = challonge.createClient({
apiKey: '***yourAPIKey***'
});
client.tournaments.create({
tournament: {
name: 'new_tournament_name',
url: 'new_tournament_url', //also can be used as id