config.json in trackler-2.0.6.4

- old
+ new

@@ -22,10 +22,15 @@
   ],
   "exercises": [
     {
       "difficulty": 1,
       "slug": "hello-world",
-      "topics": []
+      "topics": [
+          "Control-flow (if-else statements)",
+          "Optional values",
+          "Strings",
+          "Text formatting"
+      ]
     },
     {
       "difficulty": 1,
       "slug": "leap",
       "topics": []