Fixed some issues with the monthly report and missing amounts.

app/Repositories/Account/AccountRepositoryInterface.php

@@ -15,6 +15,7 @@ namespace FireflyIII\Repositories\Account;
 
 use Carbon\Carbon;
 use FireflyIII\Models\Account;
+use FireflyIII\Models\TransactionJournal;
 use Illuminate\Support\Collection;
 
 /**
@@ -105,6 +106,15 @@ interface AccountRepositoryInterface
      */
     public function newestJournalDate(Account $account): Carbon;
 
+    /**
+     * Returns the date of the very first transaction in this account.
+     *
+     * @param Account $account
+     *
+     * @return TransactionJournal
+     */
+    public function oldestJournal(Account $account): TransactionJournal;
+
     /**
      * Returns the date of the very first transaction in this account.
      *