docs: function(model, options) {
      options = options ? extend({}, options) : {};
      if (!(model = this._prepareModel(model, options))){
        return false;
      }
      if (!options.wait){
        this.add(model, options);
      }
      var collection = this;
      options.cb = options.callback;
      options.callback = function cb(err, model, response){
        if (err){
          return callback(err, model, response, options);
        }
        if (options.wait){
          collection.add(model, options);
        }
        callback(null, model, response, options);
      };
  
      model.save(null, options);
      return model;
    }