Use fast_ignore instead of git ls-files

[utkarsh2102]

Hello,

This PR does two of the following things:

• It uses fast_ignore instead of git ls-files because:

  • this way we can drop the unnecessary dependency on git.
  • use what this project is intended to do ❤️
  • ...because why not? :)

• Adds /vendor/ to the .gitignore file.
  That is because when bundle install is run, it creates a vendor/ directory which should not be committed.

Given that these are two different things, I had them committed separately.
If it makes sense, don't squash them while merging either \o/

Thanks for your work on this! 💯

[robotdana]

Perfect thank you.

I'm just cleaning up some other fixes and should have a release in half an hour or so

[utkarsh2102]

Thank you! 🎉