config.json in trackler-2.2.1.129

- old
+ new

@@ -51,11 +51,11 @@
       "slug": "two-fer",
       "topics": [
         "optional_values",
         "strings"
       ],
-      "unlocked_by": "null",
+      "unlocked_by": null,
       "uuid": "2ee3cc7a-db3f-4668-9983-ed6d0fea95d1"
     },
     {
       "core": true,
       "difficulty": 1,
@@ -124,18 +124,18 @@
       ],
       "unlocked_by": "sum-of-multiples",
       "uuid": "e7f74f6c-16ea-40d8-94f7-7034bc6ee938"
     },
     {
-      "core": false,
+      "core": true,
       "difficulty": 3,
       "slug": "beer-song",
       "topics": [
         "algorithms",
         "text_formatting"
       ],
-      "unlocked_by": "raindrops",
+      "unlocked_by": null,
       "uuid": "0ea0d92f-5510-4ba9-b419-3f5ad029b74f"
     },
     {
       "core": true,
       "difficulty": 3,
@@ -178,19 +178,19 @@
       ],
       "unlocked_by": null,
       "uuid": "ecae4faa-c516-4a71-8d55-9c53403d8826"
     },
     {
-      "core": false,
+      "core": true,
       "difficulty": 4,
       "slug": "allergies",
       "topics": [
         "bitwise_operations",
         "enumerations",
         "filtering"
       ],
-      "unlocked_by": "kindergarten-garden",
+      "unlocked_by": null,
       "uuid": "221dff26-0495-4d4b-9363-14a5d7263271"
     },
     {
       "core": true,
       "difficulty": 5,
@@ -883,11 +883,23 @@
       "slug": "spiral-matrix",
       "topics": [
         "algorithms",
         "matrices"
       ],
-      "unlocked_by": "matrix",
+      "unlocked_by": "kindergarten-garden",
       "uuid": "52f8f299-b93b-4f44-bd5b-b445741b285d"
+    },
+    {
+      "core": false,
+      "difficulty": 5,
+      "slug": "yacht",
+      "topics": [
+        "discriminated_unions",
+        "games",
+        "parsing"
+      ],
+      "unlocked_by": "space-age",
+      "uuid": "005721ef-264e-4f81-ae63-ae72b0e5310f"
     },
     {
       "core": false,
       "difficulty": 6,
       "slug": "tournament",