Move code to repository.

app/Repositories/PiggyBank/PiggyBankRepositoryInterface.php

@@ -102,6 +102,15 @@ interface PiggyBankRepositoryInterface
      */
     public function find(int $piggyBankid): PiggyBank;
 
+    /**
+     * Get current amount saved in piggy bank.
+     *
+     * @param PiggyBank $piggyBank
+     *
+     * @return string
+     */
+    public function getCurrentAmount(PiggyBank $piggyBank): string;
+
     /**
      * Get all events.
      *