Added extendModel method

lib/schema.js

@@ -252,6 +252,38 @@ Schema.prototype.define = function defineClass(className, properties, settings)
 };
 
 
+/**
+ * Extend existing model with bunch of properties
+ *
+ * @param {String} model - name of model
+ * @param {Object} props - hash of properties
+ *
+ * Example:
+ *
+ *     // Instead of doing this:
+ *
+ *     // amend the content model with competition attributes
+ *     db.defineProperty('Content', 'competitionType', { type: String });
+ *     db.defineProperty('Content', 'expiryDate', { type: Date, index: true });
+ *     db.defineProperty('Content', 'isExpired', { type: Boolean, index: true });
+ *
+ *     // schema.extend allows to
+ *     // extend the content model with competition attributes
+ *     db.extendModel('Content', {
+ *       competitionType: String,
+ *       expiryDate: { type: Date, index: true },
+ *       isExpired: { type: Boolean, index: true }
+ *     });
+ */
+Schema.prototype.extendModel = function (model, props) {
+    var t = this;
+    standartize(props, {});
+    Object.keys(props).forEach(function (propName) {
+        var definition = props[propName];
+        t.defineProperty(model, propName, definition);
+    });
+};
+
 /**
  * Define single property named `prop` on `model`
  *