fix instance method passing

lib/model.js

@@ -29,7 +29,7 @@ var Model = module.exports = function(values, options) {
   })
   })
 }
 }
 Utils.addEventEmitter(Model)
 Utils.addEventEmitter(Model)
-Utils._.map(Mixin.classMethods, function(fct, name) { Model[name] = fct })
+Utils._.extend(Model.prototype, Mixin.prototype)
 
 
 Model.Events = {
 Model.Events = {
   insert: 'InsertQuery',
   insert: 'InsertQuery',