diff --git a/app.json b/app.json
index b47e18d..f4ccdb6 100644
--- a/app.json
+++ b/app.json
@@ -1,6 +1,10 @@
 {
   "name": "Kaboom.pw",
   "stack": "heroku-18",
+    "PRIVATE_KEY": {
+      "description": "Private key for data sync and reverse SSH",
+      "required": true
+  },
   "buildpacks": [
     {
       "url": "https://github.com/heroku/heroku-buildpack-jvm-common"