code: function(alias, model, copy) {
        this.__currentObjectModels[alias] = model;
        this.__updateCache(model);
        this.resetUpdating();
        if (copy) {
          _.each(this.getMappings(), function(config, mappingAlias) {
            var modelAliases;
            if (alias === mappingAlias) {
              this.__pull(mappingAlias);
            }
            if (config.computed) {
              modelAliases = this.__getModelAliases(mappingAlias);
              if (_.contains(modelAliases, alias)) {
                this.__pull(mappingAlias);
              }
            }
          }, this);
        }
      }
docs: Update or create a binding between an object model and an alias.
  @method trackModel
  @param alias {String} the alias/name to bind to.
  @param model {Backbone Model instance} the model to be bound. Mappings referencing this alias will start applying to this model.
  @param [copy=false] {Boolean} if true, the form model will perform a pull on any mappings using this alias.