[AFP-91] 🗃 Add '#findByEmail' query to 'ManagerRepository' (@asegers)

src/main/java/com/afp/ordermanagement/repository/ManagerRepository.java

@@ -2,8 +2,10 @@ package com.afp.ordermanagement.repository;
 
 import com.afp.ordermanagement.model.Manager;
 import org.springframework.data.mongodb.repository.ReactiveMongoRepository;
-//import org.springframework.stereotype.Repository;
-//
-//@Repository
+import org.springframework.stereotype.Repository;
+import reactor.core.publisher.Mono;
+
+@Repository
 public interface ManagerRepository extends ReactiveMongoRepository<Manager, String> {
+    Mono<Manager> findByEmail(String email);
 }