Add Vercel domain configuration for bien-tuan

domains/_vercel.bientuan.json

@@ -0,0 +1,9 @@
+{
+  "owner": {
+    "username": "bien-tuan",
+    "email": "doantuanbien99@gmail.com"
+  },
+  "records": {
+    "TXT": "vc-domain-verify=bientuan.is-a.dev,69667ddec653b8d51f7c"
+  }
+}