Add contributing information

Author: HeikoKlare

CONTRIBUTING.md

@@ -1,4 +1,17 @@
-# Contributing to Eclipse Platform
-See https://github.com/eclipse-platform/.github/blob/main/CONTRIBUTING.md for contributing to Eclipse Platform in general.
+# Contributing to Initiative 31's Skija Prototype
 
-Additional SWT-specific information can be found in [README.md](README.md).
+Thank you for your interest in contributing to this SWT prototyping work.
+
+## Setup and Contribution Workflow
+
+To set up a development environment for testing and developing the prototype, please see the prototype-specific information in the [README](README.md) and the general information about setting up a development environment for Eclipse in the [contributing information](https://github.com/eclipse-platform/.github/blob/main/CONTRIBUTING.md) of the Eclipse platform.
+There, you can also find information about how to make pull requests for providing parts that you have implemented to this repository.
+You can also reach out to any of the [people involved so far](https://github.com/orgs/swt-initiative31/people) or use our [communication channels](https://github.com/swt-initiative31#contacts) to find out how to contribute your work.
+
+## Potential Work Items
+
+Since this work is still in a prototyping phase with limited resources, we do not a defined roadmap towards a full SWT implementation based on Skia and custom-implemented widgets yet.
+Still, we have a list of general tasks that we do currently or need to work on:
+- [Roadmap / Tasks](https://github.com/swt-initiative31/prototype-skija/issues/14)
+
+You can have a look into that list to find out which topics might be of interest for you. A good starting point to get familiar with the work is to pick any of the controls that are not custom-implemented so far and try to implement them on your own, i.e., without using the current native implementation of that widget. In case you have any questions on that, please comment to that issue, reach out to any of the current contributors to the project or join any of our [communication channels](https://github.com/swt-initiative31#contacts).

README.md

@@ -4,6 +4,10 @@ This repository is a fork of the original [SWT repository](https://github.com/ec
 
 In the following, you find information about the current state of the prototype and how to try it out. Note that the prototype does currently not provide other/better look and feel or customizability compared to the native widgets. It is supposed to demonstrate feasibility to custom draw widgets based on an efficient rendering engine (as an enabler for improved customizability and look and feel) while seamlessly integrating the custom-drawn widgets with the other, still native widgets. For that reason, the custom-drawn widgets are currently implemented to look similar to the existing widgets they replace, but they could be easily replaced with whatever look and feel is desired.
 
+## How to Contribute
+
+See our [contributing information](CONTRIBUTING.md) to find out how to contribute.
+
 ## Getting Started
 
 To test the prototype, an Eclipse IDE has to be set up and the SWT projects from this repository have to be imported into it to start example applications.