fix initialization for int64 CWItems map

obj.go

@@ -681,7 +681,7 @@ func addObjItem(code string, name string, itemTypeID64 int64, weight int, exchan
 	cacheObjItem[name] = *c
 
 	muxObjItemId.Lock()
-	cacheObjItemId[objId] = *c
+	cacheObjItemId[c.ObjID64] = *c
 	defer muxObjItemId.Unlock()
 
 	return objId, nil
@@ -783,6 +783,10 @@ func loadObjItem() error {
 	cacheObjItem = make(map[string]ChatWarsItem)
 	muxObjItem.Unlock()
 
+	muxObjItemId.Lock()
+	cacheObjItemId = make(map[int64]ChatWarsItem)
+	muxObjItemId.Unlock()
+
 	items, err := db.Query(`SELECT oi.obj_id, oi.intl_id, obn.name, oi.weight FROM obj_item oi, obj_name obn WHERE obn.obj_id = oi.obj_id AND obn.priority = 0;`)
 	if err != nil {
 		return err