Add leanhdung.json for domain configuration

domains/leanhdung.json

@@ -0,0 +1,9 @@
+{
+  "owner": {
+    "username": "dungx-o",
+    "email": "leadungx@gmail.com"
+  },
+  "record": {
+    "CNAME": "dungx-o.github.io"
+  }
+}