Refactor DNS records structure in tungnm15.json

Updated JSON structure to use 'records' key for DNS entries.

domains/tungnm15.json

@@ -6,11 +6,13 @@
     "username": "coderviet1111",
     "email": "khongbiettimtennao@gmail.com"
   },
-  "record": {
+  "records": {
     "MX": [
       { "priority": 10, "value": "mx1.improvmx.com" },
       { "priority": 20, "value": "mx2.improvmx.com" }
     ],
+    "A": ["1.2.3.4"],
+    "CNAME": "tungnm15.github.io",
     "TXT": [
       "v=spf1 include:spf.improvmx.com ~all"
     ]