Add my Undertale RP server

IDK if that's fine. Also, I have no idea if what I edited is good or not, haven't gotten into JavaScript yet and had to copy-paste some of that.

data/serverlist.json

@@ -776,6 +776,13 @@
       "icon": null,
       "language": "EN",
       "title": "Rivals of Aether"
+    },
+    "BOUNDARIES UNDERTALE": {
+      "code": "0kOFr0tF9gwI5I4d",
+      "description": "An Undertale RP server",
+      "icon": null,
+      "language": "EN",
+      "title": "=||BOUNDARIES UNDERTALE||="
     }
   }
 }