Lint set up with Husky pre-commit hook

[treystevens]

Intended / expected behavior with "pre-commit": "npm run lint" in our package.json:

1. Files in staging have lint errors
2. Lint errors are fixed with a pre-commit hook
3. Files pushed to GitHub with the lint fix

Actual behavior:

1. Files in staging have lint errors
2. Lint errors are fixed with a pre-commit hook
3. Files in step 1 prior to npm run lint are committed instead of the newly modified files after running the pre-commit hook