Add Vercel configuration for phuocthinh domain

domains/_vercel.phuocthinh.json

@@ -0,0 +1,9 @@
+{
+    "owner": {
+        "username": "CSerVN",
+        "email": "summerthinh3@gmail.com"
+    },
+    "records": {
+        "TXT": ["vc-domain-verify=phuocthinh.is-a.dev,5d6050dfb5b233daa3b3"]
+    }
+}