Basic readme for playground

browser-playground/README.md

@@ -1,9 +1,31 @@
-## Development
+# browser-playground
 
-Install dependencies locally, unfortunately via the workspace is not enough to run `webpack-dev-server`. Then
+This is a web-based playground hosting the [language server](../actions-languageserver/) in a web worker connected to an instance of the [Monaco](https://microsoft.github.io/monaco-editor/) editor. You can try it at https://actions.github.com/languageservices.
+
+## Contributing
+
+### Build and run
+
+Even though the package is part of the `npm` workspace, it needs its dependencies to be installed locally in order to run `webpack-dev-server`. To do so, run:
+
+```bash
+$ npm i --workspaces=no
+```
+
+then
 
 ```bash
 $ npm start
 ```
 
-to serve the app at `localhost:8080`.
+to build and serve the app at `localhost:8080`.
+
+## Contributing
+
+See [CONTRIBUTING.md](../CONTRIBUTING.md) at the root of the repository for general guidelines and recommendations.
+
+If you do want to contribute, please run [prettier](https://prettier.io/) to format your code before submitting your PR.
+
+## License
+
+This project is licensed under the terms of the MIT open source license. Please refer to [MIT](../LICENSE) for the full terms.