Add Heroku generated app.json

Author: mattheworiordan

app.json

@@ -0,0 +1,17 @@
+{
+  "name": "tutorials",
+  "scripts": {
+  },
+  "env": {
+  },
+  "formation": {
+  },
+  "addons": [
+    "ably"
+  ],
+  "buildpacks": [
+    {
+      "url": "heroku/nodejs"
+    }
+  ]
+}