Bootstrapping the System, Part 2: Where the Settings Come From (Chapter 13)

Part 1 left the application with a complete set of beans and no way to start. Both PersistenceConfiguration and FlywayConfiguration take a HikariDataSource as a parameter, nothing declares one, and a datasource needs three things that cannot be committed to a repository: a URL, a username and a password. The lazy fix is a local.properties with all three in it, gitignored, and a note in the README. That works on a laptop and nowhere else. The application also has to start in a container, where t