- Added Flyway sql scripts

- Added SQL constraints added to respective tables see list below:
-- video_playlist: video_id playlist_id
-- Foreign keys reference originals, on delete cascade on both
- Added Java JPA Entity column name mapping to snake_case instead of using base Java camelCase

src/main/resources/application.properties

@@ -2,4 +2,8 @@ spring.application.name=video_downloader
 spring.datasource.url = jdbc:postgresql://127.0.0.1:5432/videos
 spring.datasource.username = postgres
 spring.datasource.password = 5995
-spring.jpa.hibernate.ddl-auto = create-drop
+spring.jpa.hibernate.ddl-auto = none
+logging.level.org.flywaydb=DEBUG
+logging.level.org.springframework.boot.autoconfigure.flyway=DEBUG
+spring.flyway.enabled=true
+spring.flyway.baseline-on-migrate=true