diff --git a/dbs/mongo/mongo.go b/dbs/mongo/mongo.go
index 9234006..22ee69e 100644
--- a/dbs/mongo/mongo.go
+++ b/dbs/mongo/mongo.go
@@ -247,7 +247,7 @@ func (m *MongoDB) StoreOne(obj interface{}, id string, collection_name string) (
 	if err := m.createClient(mngoConfig.GetUrl(), false); err != nil {
 		return "", 503, err
 	}
-	var doc map[string]interface{}
+	doc := map[string]interface{}{}
 	b, _ := bson.Marshal(obj)
 	bson.Unmarshal(b, &doc)
 	doc["_id"] = id