Run checkstyle

Configured based on: https://checkstyle.org/

mvn checkstyle:checkstyle

Test

http://localhost:8081/ping

Welcome to Master Diet

App time:       2020-10-19T17:12:00.239871Z[UTC]

Database time:  2020-10-19T17:12:00.670Z[UTC]

Swagger API documentation

http://localhost:8081/swagger-ui.html