fix(stock price checker): add missing function return (#612)

Author: lasjorg

apps/stock-price-checker/controllers/stockHandler.js

@@ -82,7 +82,7 @@ function StockHandler() {
 const validTickerRegExp = /^[a-z]{1,6}$/;
 const isValidStock = stock => {
   const stockL = stock.toLowerCase().trim();
-  validTickerRegExp.test(stockL);
+  return validTickerRegExp.test(stockL);
 };
 
 module.exports = StockHandler;