add method GetUsers, and array type Users -> []User

internal/user/service.go

@@ -42,6 +42,13 @@ func (s *Service) Create(user *User) error {
 	return s.store.Create(user)
 }
 
+func (s *Service) GetUsers() (Users, error) {
+	if !s.isInitialized() {
+		return nil, fmt.Errorf("user service is not initialized")
+	}
+	return s.store.GetUsers()
+}
+
 func (s *Service) GetBy(by, value string) (*User, error) {
 	if !s.isInitialized() {
 		return nil, fmt.Errorf("user service is not initialized")