Spring Boot - REST - MongoDB (and PostgreSQL/Liquibase)

There is an existing back end codebase, we need to finish all missing requirements in 3 weeks, and 1 week for testing and bug fixes.

There are two parallel tasks:

1- To fulfill the missing requirements, using MongoDB. This involves cooperation with the front-end team (a separate existing team).
2- To migrate existing (and new) queries from MongoDB to PostgreSQL using Liquibase.

Multiple hires would happen, and each contract would be evaluated twice: one after two days, another one after one week.

We would start by one member for each task, and add more whenever needed.

The current OpenAPI (Swagger) is in http://mcit-drs.herokuapp.com/swagger-ui/index.html

- Latest versions are used (except using Java 18 because of Heroku).
- Code first API
- The application is automatically deployed, with updated OpenAPI, to be used by the front-end team.

Regarding the migration to PostgreSQL, we need to gradually add corresponding endpoints, so that we have duplication, till we remove the MongoDB ones.
Hibernate would be used to create the schema, and Liquibase would be used to create the 'update' files. Initial entities exist.

Please don't submit if you aren't experienced with those technologies.