Merge pull request #179 from saschagehlich/master

updateAttributes: data defaults to {}

lib/abstract-class.js

@@ -721,6 +721,8 @@ AbstractClass.prototype.updateAttributes = function updateAttributes(data, cb) {
     var inst = this;
     var model = this.constructor.modelName;
 
+    if(!data) data = {};
+
     // update instance's properties
     Object.keys(data).forEach(function (key) {
         inst[key] = data[key];