Update README.md (#891)

Add a Contributing section and the Buy Me A Coffee link since I had to hunt for it.

Author: grbray

README.md

@@ -30,6 +30,14 @@ docker run -d \
 # ghcr.io/hay-kot/homebox:latest-rootless
 ```
 
+<!-- CONTRIBUTING -->
+## Contributing
+
+Contributions are what make the open source community such an amazing place to learn, inspire, and create. Any contributions you make are **greatly appreciated**.
+
+If you are not a coder, you can still contribute financially. Financial contributions help me prioritize working on this project over others and helps me know that there is a real demand for project development.
+
+<a href="https://www.buymeacoffee.com/haykot" target="_blank"><img src="https://cdn.buymeacoffee.com/buttons/v2/default-green.png" alt="Buy Me A Coffee" style="height: 30px !important;width: 107px !important;" ></a>
 ## Credits
 
 - Logo by [@lakotelman](https://github.com/lakotelman)