Add Overcommit

[markolson]

Overcommit will run checks using git hooks against any staged code and commit messages before allowing the code to be committed or pushed. This example .overcommit.yml file follows what I've tended to use on past projects.

It's opt-in by running the overcommit --install --sign command, and can always be disabled or overridden if needed. Any changes made to the .overcommit.yml file or any plugins require overcommit --sign to be run again.

For an example of how it works, make one of the yaml configuration files invalid and try to commit it.

🚲 🏠

[robbiethegeek-usds]

Not sure that this should be optional for local development... @aub thoughts? @jkassemi (for vision)

[jkassemi]

I'll speak to CI integration and not to the update to developer workflow. There's some functionality overlap with rubocop (newline detection), but we can throw this into the Jenkinsfile (or as part of the ci rake task).

[markolson]

I'm not entirely sure about the benefit of adding this to Jenkins, especially given the need to sign the .overcommit file whenever it changes. We'd have to run overcommit -r, which scans the entire repo instead of the just staged commits and could catch a lot more than is strictly necessary for the PR/branch itself.

[aub]

@markolson is it even possible to make it non-optional? I think it looks good but might change the language in the README to something that makes it seem more imperative, or at least gives a reason why one should install it.

[markolson]

Can do. I'll also change bin/setup as part of this to do a lot of what the README suggests, including enabling overcommit.

[aub]

@markolson that sounds perfect!

[markolson]

@aub I've added a (very likely overly complex) setup script for people using OS X which enables overcommit as part of the setup process.

[aub]

Ok, this looks great. One last thing... does the README contain instructions to run your setup script? I think we're good to merge if we have that.

[markolson]

@aub Updated the README. I also did a run-through where I deleted my homebrew, rubies, postgres, and redis and the script got me setup and running.

[aub]

!!! Awesome, let's do this.