Add a CONTRIBUTING.md with basic dev setup instructions

[bbrowning]

This isn't exhaustive, but should give a basic starting point for anyone wanting to work on SDG locally.

[bbrowning]

I've had a couple of people need to know how to get SDG setup for local development in the last few days, so it's time to add something to our repo to point them in the right direction.

[RobotSail]

LGTM

[nathan-weinberg]

It may be good to have this be a more traditional CONTRIBUTING.md

We have a general one of these in the Community repo: https://github.com/instructlab/community/blob/main/CONTRIBUTING.md

And also one in the Core repo: https://github.com/instructlab/instructlab/blob/main/CONTRIBUTING/CONTRIBUTING.md

[RobotSail]

@nathan-weinberg I do like the format of the files you've linked and find them to be comprehensive, though I've also found the simple format of DEVELOPMENT.md presented here to be be very readable and simple for just getting started.

[nathan-weinberg]

@nathan-weinberg I do like the format of the files you've linked and find them to be comprehensive, though I've also found the simple format of DEVELOPMENT.md presented here to be be very readable and simple for just getting started.

I'm fine to keep the current content, but I would like if we could rename this to CONTRIBUTING.md for cross-project consistency

@bbrowning wdyt?

[bbrowning]

@nathan-weinberg That was just an old habit of mine to call this DEVELOPMENT.md - renamed to CONTRIBUTING.md for consistency. Thanks for catching that!

[bbrowning]

Thanks for the reviews!