refactor(user): from class to interface

Author: javajigi

src/main/java/nextstep/users/infrastructure/JdbcUserRepository.java

@@ -15,7 +15,7 @@
 public class JdbcUserRepository implements UserRepository {
     private JdbcOperations jdbcTemplate;
 
-    public JdbcUserRepository(JdbcTemplate jdbcTemplate) {
+    public JdbcUserRepository(JdbcOperations jdbcTemplate) {
         this.jdbcTemplate = jdbcTemplate;
     }