create database conduitspring;
create user conduitspring with encrypted password 'conduitspring';
grant all privileges on database conduitspring to conduitspring;

create database conduitspring;
create user conduitspring identified by 'conduitspring';
grant all privileges on conduitspring.* to conduitspring;

Add file system.properties

java.runtime.version=11

This tells Heroku which Java version to use.

Heroku provides it's own port. To use that ...

server:
  port: ${PORT:4567}

This means, use $PORT environment variable if available, or if that is null, use 4567

If application.yaml or application.properites has Postgres driver, then heroku installs Postgres automatically. Otherwise deploy Postgres addon (free tier is fine)

Add config params

spring:
  datasource:
    url: ${SPRING_DATASOURCE_URL:jdbc:postgresql://localhost:5432/conduitspring}
    username: ${SPRING_DATASOURCE_USERNAME:conduitspring}
    password: ${SPRING_DATASOURCE_USERNAME:conduitspring}
    driver-class-name: org.postgresql.Driver