config.json in trackler-2.0.3.8

- old
+ new

@@ -22,10 +22,11 @@
 		},
     {
       "slug": "sum-of-multiples",
       "difficulty": 1,
       "topics": [
-	    "Filtering"
+	    "Filtering", 
+            "Sets"
       ]
 		},
     {
       "slug": "hamming",
       "difficulty": 2,