Skip Circle CI builds for certain ignored paths

I recently put together a monorepo that mixes a lot of content (e.g. blog posts) with a lot of code (e.g. backend APIs). Because every typo fix was kicking off a pretty intense CI build, I wanted a way to automatically detect when a given git changeset didn't warrant running a CI build and to skip it automatically.

This repo does that by ignoring changes in .ciignore files (currently the README.md and content/ directories) between any two given git revisions.

To see how this is accomplished check out:

• .circleci/config.yml
• script/skip_build_if_ignored_paths