message: Default to empty object if models are not provided to a schema
diff: @@ -108,6 +108,10 @@ export default class Schema implements Evented, RecordInitializer {
  settings.version = 1;
  }
  + if (settings.models === undefined) {
  + settings.models = {};
  + }
  +
  this._applySettings(settings);
  }
  