Hooks for pre-commit that validate Elm files

• To use this you first need to install pre-commit
• Run pre-commit install from the root of your project

Finally add this to your .pre-commit-config.yaml:

- repo: https://github.com/a-ibs/pre-commit-mirrors-elm-format
  rev: 1.0.0
  hooks:
    - id: elmformat

Now when you try to commit an Elm file, it will run elm-format and prevent commit if the checks fail.