Integrate with Coveralls for test coverage

[Alex Klibisz]

Background

I'd like to be able to track and visualize code coverage for large changes.
Coveralls seems like a good first option to try: they have a free open-source tier, and the
sbt-scoverage plugin supports integration (https://github.com/scoverage/sbt-scoverage#coveralls).

Deliverables

• Scoverage for test coverage on PRs
• Integration with coveralls to link from PRs to coveralls reports

Related Issues

No response