docs: Guide for contribution

Author: timonback

README.md

@@ -16,6 +16,18 @@ dependencies {
 
 After starting the application, visit: `localhost:8080/springwolf/asyncapi-ui.html`.
 
+## Contribution
+
+You are welcome to raise issues and contribute code.
+
+### Code contribution
+
+Just fork the project, write code and open a PR.
+
+This repository uses github actions. We recommend activating them in your fork and open a PR within your fork to trigger them.
+
+Also, to build a preview for your branch, you can sign up to [Netlify's](https://app.netlify.com) free tier with your github account, import a new site from your github fork and set the build command as described in `src/_redirects`. Open a PR in within your fork and update the code to trigger a build.
+
 ## Development
 1. Run `npm i`
 2. Run `ng serve`