model validations on create

bb.js

// in Model:

  Backbone.Model = function(attributes, options) {
    this.attributes = {};
    this.cid = _.uniqueId('c');
    options = _.extend({silent:true}, options || {});
    this.set(attributes || {}, options);
    this._previousAttributes = _.clone(this.attributes);
    if (this.initialize) this.initialize(attributes);
  };




// in Collection:

    _add : function(model, options) {
      options || (options = {});
      if (!(model instanceof Backbone.Model)) {
        model = new this.model(model, options);
      }
      var already = this.getByCid(model);
      if (already) throw new Error(["Can't add the same model to a set twice", already.id]);
      this._byId[model.id] = model;
      this._byCid[model.cid] = model;
      model.collection = this;
      var index = this.comparator ? this.sortedIndex(model, this.comparator) : this.length;
      this.models.splice(index, 0, model);
      model.bind('all', this._boundOnModelEvent);
      this.length++;
      if (!options.silent) this.trigger('add', model);
      return model;
    },