RVRNEXT-5 add model and repository for currencies

src/Repository/CurrencyRepository.php

@@ -0,0 +1,32 @@
+<?php namespace RVR\Repository;
+
+use Generator;
+use Container;
+use RVR\PersistentData\Model\Community;
+use RVR\PersistentData\Model\Currency;
+use SokoWeb\Database\Query\Select;
+
+class CurrencyRepository
+{
+    public function getById(int $id): ?Currency
+    {
+        return \Container::$persistentDataManager->selectFromDbById($id, Currency::class);
+    }
+
+    public function getAllByCommunity(Community $community, bool $useRelations = false): Generator
+    {
+        $select = new Select(Container::$dbConnection);
+        $select->where('community_id', '=', $community->getId());
+
+        yield from Container::$persistentDataManager->selectMultipleFromDb($select, Currency::class, $useRelations);
+    }
+
+    public function getByCommunityAndCurrencyCode(Community $community, string $code): ?Currency
+    {
+        $select = new Select(Container::$dbConnection);
+        $select->where('community_id', '=', $community->getId());
+        $select->where('code', '=', $code);
+
+        return Container::$persistentDataManager->selectFromDb($select, Currency::class);
+    }
+}