constructor(models = []) {
    this.models = models;
  }
An array of models, returned from one of the schema query
methods (all, find, where). Knows how to update and destroy its models.

Identical to Collection except it can contain a heterogeneous array of
models. Thus, it has no `modelName` property. This lets serializers and
other parts of the system interact with it differently.

@class PolymorphicCollection
@constructor
@public
@hide