Update README.md (#21)

Add hipscat's contribution guide, and update acknowledgement text.

README.md

@@ -103,3 +103,15 @@ def storage_options(cloud):
 1. REPOSITORY secrets
 1. smoke_test.yml
 1. testing-and-coverage
+
+
+## Contributing
+
+[![GitHub issue custom search in repo](https://img.shields.io/github/issues-search/astronomy-commons/hipscat-cloudtests?color=purple&label=Good%20first%20issues&query=is%3Aopen%20label%3A%22good%20first%20issue%22)](https://github.com/astronomy-commons/hipscat-cloudtests/issues?q=is%3Aissue+is%3Aopen+label%3A%22good+first+issue%22)
+
+See the [hipscat contribution guide](https://hipscat.readthedocs.io/en/latest/guide/contributing.html)
+for contribution best practices.
+
+## Acknowledgements
+
+This project is supported by Schmidt Sciences.