diff --git a/config.json b/config.json
index 0cad7cf6..196b43a7 100644
--- a/config.json
+++ b/config.json
@@ -33,6 +33,9 @@
     ]
   },
   "exercises": {
+    "foregone": [
+      "parallel-letter-frequency"
+    ],
     "concept": [
       {
         "slug": "lasagna",