Modify Example 5 to persist objects in H2 database

in the file application.properties

# added these lines to make H2 database persist objects between runs
spring.datasource.url=jdbc:h2:db/videodb;AUTO_SERVER=TRUE
spring.datasource.driverClassName=org.h2.Driver
spring.jpa.show-sql: true
spring.jpa.hibernate.ddl-auto=update