Getting Started with SimpleCov in GitLab CI

I spent a good chunk of this past weekend trying to integrate SimpleCov into a framework called Marty that we work on at my company, PennyMac Loan Services.We use GitLab CI at PennyMac for continuous development workflows, and while it's a fantastic piece of software, getting it to work with a code coverage tool like SimpleCov is not quite a "batteries included" situation.