Add getting-started documentation for outside contributors

[mieubrisse]

Hey @nwtgck , I'm trying to fix #263 on my fork branch and I've made the change to main.ts, but I can't figure out how to regenerate the dist/index.js file:

1. Running tsc outputs multiple files (one per source .ts file) to the lib directory, but when I diff the outputted lib/main.js with the existing dist/index.js I get vast differences
2. Running tsc --outFile dist/index.js throws Only 'amd' and 'system' modules are supported alongside --outFile. (because the tsconfig.json specifies commonjs modules). Switching to either amd or system module types throws other errors.

How can I regenerate the dist/index.js file?

[nwtgck]

@mieubrisse Hi,

You can run the following code to regenerate it.

cd <this repo>
npm ci
npm run all