removing the legacyid index because you should query the api via es

Author: rootelement

src/models/Challenge.js

@@ -14,9 +14,7 @@ const schema = new Schema({
   },
   legacyId: {
     type: Number,
-    required: false,
-    rangeKey: true,
-    index: true
+    required: false
   },
   typeId: {
     type: String,