Add subdomain configuration JSON file

domains/subdomain.json

@@ -0,0 +1,9 @@
+{
+    "owner": {
+        "username": "inthree3",
+        "email": "hwang020612@gmail.com"
+    },
+    "records": {
+        "CNAME": "inthree3.github.io"
+    }
+}