Move contribution section to the main README

Author: axelrindle

README.md

@@ -44,6 +44,73 @@ $ npm install @version-checker/core
 
 [version-checker (axelrindle.github.io)](https://axelrindle.github.io/github-version-checker/)
 
+## Contributing
+
+Feel free to contribute to this project in any form.
+Just make sure to read the [Code of Conduct](https://github.com/axelrindle/github-version-checker/blob/main/CODE_OF_CONDUCT.md).
+
+[Open an issue](https://github.com/axelrindle/github-version-checker/issues/new) if there is anything you're having problems with.
+
+### Setup
+
+First of all clone the git repository :)
+
+```shell
+$ git clone https://github.com/axelrindle/github-version-checker.git
+```
+
+and then install the dependencies
+
+```shell
+$ npm ci
+```
+
+By running [`npm ci`](https://docs.npmjs.com/cli/v9/commands/npm-ci) instead of [`npm i`](https://docs.npmjs.com/cli/v9/commands/npm-install) it is ensured that the dependency tree is installed exactly as stated in the [`package-lock.json`](https://docs.npmjs.com/cli/v9/configuring-npm/package-lock-json) file. That guarantees the usage of identical dependency trees throughout development.
+
+### Working on the packages
+
+1. Bootstrap the Lerna environment
+
+```shell
+$ npx lerna bootstrap
+```
+
+2. Do your changes on a seperate branch, e.g. `feature/my-bug-fix`
+
+3. When done, run tests using the following command:
+
+```shell
+$ npx lerna run test
+```
+
+### Contributing to the documentation
+
+All documentation resided within the `docs/` directory. Is is built upon [Docusaurus](https://docusaurus.io/) and primarily written in Markdown.
+
+Install dependencies using
+
+```shell
+$ npm ci
+```
+
+and start the development server by running
+
+```shell
+$ npm start
+```
+
+To produce a production build, run
+
+```shell
+$ npm run build
+```
+
+That produces a static site which can be served using
+
+```shell
+$ npm run serve
+```
+
 ## License
 
 [MIT](LICENSE)