Some customers are requesting Oracle support.
Technically we can support it thanks to use of Doctrine DBAL, however we need to test it to see how much effort is needed to support it.
So we should either get travis (our CI system) to run with it or manually setup oracle and try to run all tests suites with this.
For possible solutions on running oracle on travis:
Main issue is licensing, so might need to reach out to Oracle on behalf of open source software that wants to support oracle db.