docs: update README with dev instructions

Author: sgratzl

README.md

@@ -1,3 +1,5 @@
+# Delphi EpiVis
+
 [![License: MIT][mit-image]][mit-url] [![Github Actions][github-actions-image]][github-actions-url] [![Netlify Status][netlify-image]][netlify-url]
 
 An interactive tool for visualizing epidemiological time-series data.
@@ -15,6 +17,52 @@ Little piece of trivia: the first version of EpiVis was written on 2014-12-22.
 See the git history of this file for a legacy changelog which describes changes
 made prior to the migration to git around 2017.
 
+## Development Environment
+
+One click solution: [![Open in Gitpod](https://gitpod.io/button/open-in-gitpod.svg)](https://gitpod.io/#https://github.com/cmu-delphi/www-epivis)
+
+`node` and `npm` are required for development.
+
+To begin development, clone this repository and run
+
+```sh
+npm install
+```
+
+To lint or check for styling, run
+
+```sh
+npm run lint
+```
+
+To run unit test, run
+
+```sh
+npm test
+```
+
+To run the development server, run
+
+```sh
+npm start
+```
+
+the website is then accessible via: http://localhost:8080/
+
+### Release Process
+
+The release consists of multiple steps which can be all done via the GitHub website:
+
+1. Go to [create_release GitHub Action](https://github.com/cmu-delphi/www-epivis/actions/workflows/create_release.yml) and click the `Run workflow` button. Enter the next version number or one of the magic keywords (patch, minor, major) and hit the green `Run workflow` button.
+1. The action will prepare a new release and will end up with a new [Pull Request](https://github.com/cmu-delphi/www-epivis/pulls)
+1. Let the code owner review the PR and its changes and let the CI check whether everything builds successfully
+1. Once approved and merged, another GitHub action job starts which automatically will
+   1. create a git tag
+   1. create another [Pull Request](https://github.com/cmu-delphi/www-epvis/pulls) to merge the changes back to the `dev` branch
+   1. create a [GitHub release](https://github.com/cmu-delphi/www-epivis/releases) with automatically derived release notes
+   1. create a [Pull Request in www-main](https://github.com/cmu-delphi/www-main/pulls) to update the website to the new release
+1. Done
+
 ## License
 
 This repository is released under the **MIT License**.