disable gob register if cache is not enabled

engine.go

@@ -664,12 +664,14 @@ func (engine *Engine) autoMapType(v reflect.Value) *core.Table {
 	if !ok {
 		table = engine.mapType(v)
 		engine.Tables[t] = table
+		if engine.Cacher != nil {
 			if v.CanAddr() {
 				engine.GobRegister(v.Addr().Interface())
 			} else {
 				engine.GobRegister(v.Interface())
 			}
 		}
+	}
 	engine.mutex.Unlock()
 	return table
 }