code: function(model_s, create, options){
        var toAdd = model_s instanceof Array ? model_s : [model_s],
            self = this;
  
        ko.utils.arrayForEach(toAdd, function(attributes){
          var model;
          if(attributes instanceof Model){
            model = attributes;
            model.collection = self;
          }else{
            model = new self.model(attributes, {collection: self});
          }
          self.models.push(model);
          if(create) model.save(options);
        });
      }
docs: Add one or more models to collection and optionally create them on the server setting the 'create' parameter to 'true' It will also add a reference to the collection on each model