Create CONTRIBUTING.md

[swyxio]

surprisngly enough i stumbled into a few pitfalls when trying to contribute. here is a simple checklist and it also makes clear we do welcome contributions

[hedgerh]

I wanted to suggest a note on using yarn link tsdx to use the local development copy when running the yarn scripts inside of a TSDX project, but got carried away and ended up reformatting the contribution guide. Thoughts?

Contributing to TSDX

Thanks for your interest in TSDX! You are very welcome to contribute. If you are proposing a new feature, make sure to open an issue to make sure it is inline with the project goals.

Setup

0. First, remove any existing tsdx global installations that may conflict.

   yarn global remove tsdx
   npm uninstall -g tsdx
   

1. Fork this repository to your own GitHub account and clone it to your local device:

   git clone https://github.com/your-name/tsdx.git
   cd tsdx
   

2. Install the dependencies and build the Typescript files to Javascript:

   yarn install
   yarn build
   

   Note: you'll need to run yarn build any time you want to see your changes.

3. Make it so running tsdx anywhere will run your local dev version:

   yarn link
   

4. To use your local version when running yarn build/yarn start/yarn test in a TSDX project, run this in the project:

   yarn link tsdx
   

   You should see a success message: success Using linked package for "tsdx". The project will now use the locally linked version instead of a copy from node_modules.

Submitting a PR

Be sure to run yarn test before you make your PR to make sure you haven't broken anything.

[swyxio]

@hedgerh i have updated the doc with your edits, cheers https://github.com/palmerhq/tsdx/blob/master/CONTRIBUTING.md