Ao acessar a API do projeto no Heroku (http://cdc-react.herokuapp.com/api/livros) está retornando erro 500:
Whitelabel Error Page
This application has no explicit mapping for /error, so you are seeing this as a fallback.
Thu May 16 00:08:51 UTC 2019
There was an unexpected error (type=Internal Server Error, status=500).
Could not open JPA EntityManager for transaction; nested exception is org.hibernate.exception.SQLGrammarException: Could not open connection
