Add semicolon for tdd exports

test/groupBy/groupBy.js

@@ -3,4 +3,4 @@ arr.map(typeof fn === 'function' ? fn : val => val[fn]).reduce((acc, val, i) =>
 acc[val] = (acc[val] || []).concat(arr[i]);
 return acc;
 }, {});
-module.exports = groupBy
+module.exports = groupBy;