addcollection.add(models, [options]) Add a model (or an array of models) to the collection, firing an "add" event for each model, and an "update" event afterwards. If a model property is defined, you may also pass raw attributes objects, and have them be vivified as instances of the model. Returns the added (or preexisting, if duplicate) models. Pass {at: index} to splice the model into the collection at the specified index. If you're adding models to the collection that are already in the co