config.json in trackler-2.2.1.154

- old
+ new

@@ -147,11 +147,11 @@
         "strings"
       ],
       "unlocked_by": null,
       "uuid": "8b29da0e-8ead-4e72-a12a-d448c8434767"
     },
-    {
+	{
       "core": true,
       "difficulty": 2,
       "slug": "grains",
       "topics": [
         "bitwise_operations",
@@ -908,10 +908,22 @@
       "unlocked_by": "error-handling",
       "uuid": "408f235e-f1ce-11e7-8c3f-9a214cf093ae"
     },
     {
       "core": false,
+      "difficulty": 4,
+      "slug": "linked-list",
+      "topics": [
+        "pointer",
+        "data_structure"
+      ],
+      "unlocked_by": "tree-building",
+      "uuid": "4368df53-39fb-4f36-97c2-39c399cd6d25"
+    },
+
+    {
+      "core": false,
       "difficulty": 5,
       "slug": "binary-search",
       "topics": [
         "algorithms",
         "arrays",
@@ -1070,11 +1082,11 @@
         "text_formatting"
       ],
       "unlocked_by": "twelve-days",
       "uuid": "a7469032-c4d0-4e15-aa0c-4e9f6588b4c8"
     },
-    { 
+    {
       "core": false,
       "difficulty": 4,
       "slug": "yacht",
       "topics": [
         "equality",
@@ -1338,10 +1350,9 @@
       "slug": "trinary",
       "uuid": "52af9f03-8b6b-4d75-a363-124f3269dccd"
     }
   ],
   "foregone": [
-    "linked-list"
   ],
   "ignore_pattern": "example(?!.*test)",
   "language": "Go"
 }