lib/indexed_collection_mixin.js
function(model, options) {
    options = options ? _.clone(options) : {};
    if (!(model = this._prepareModel(model, options))) return false;
    if (!options.wait) this.add(model, options);
    return this._callAdapter('addToIndex', options, model);
  }
function(model, options) {
    options = options ? _.clone(options) : {};
    if (!(model = this._prepareModel(model, options))) return false;
    if (!options.wait) this.add(model, options);
    return this._callAdapter('addToIndex', options, model);
  }
function ( model , options ) { options = options ? _ . clone ( options ) : { } ; if ( ! ( model = this . _prepareModel ( model , options ) ) ) return false ; if ( ! options . wait ) this . add ( model , options ) ; return this . _callAdapter ( 'addToIndex' , options , model ) ; }
Adds a new model key to the index.
@param {Model} model   model whose key (id) is added to index
@param {Object} options options
@returns {Promise} promise
Adds a new model key to the index .