añadido todo lo referente a paises

src/main/java/com/imprimelibros/erp/paises/PaisesRepository.java

@@ -0,0 +1,16 @@
+package com.imprimelibros.erp.paises;
+
+import org.springframework.data.jpa.repository.JpaRepository;
+import org.springframework.stereotype.Repository;
+
+import java.util.Optional;
+
+@Repository
+public interface PaisesRepository extends JpaRepository<Paises, String> {
+
+    Optional<Paises> findByCode(String code);
+
+    Optional<Paises> findByCode3(String code3);
+
+    Optional<Paises> findByCurrency(String currency);
+}