- Добавил аутентификацию с помощью Spring Security.

- Реализовал кастомные  CustomUserDetails и CustomUserDetailsService

https://www.youtube.com/watch?v=WDlifgLS8iQ&list=PLU2ftbIeotGoGSEUf54LQH-DgiQPF2XRO&index=3
https://spring.io/guides/gs/securing-web
https://medium.com/@CodeWithTech/spring-security-with-jdbcuserdetailsmanager-and-custom-userdetailsservice-a-complete-guide-248ddce0196c

src/main/resources/application.properties

@@ -3,4 +3,5 @@ spring.datasource.url=jdbc:mysql://${MYSQL_HOST:localhost}:3306/sweater_db
 spring.datasource.username=user
 spring.datasource.password=123456
 spring.datasource.driver-class-name=com.mysql.cj.jdbc.Driver
+spring.mustache.servlet.expose-request-attributes=true