Add references to README

Author: Suiram1701

README.md

@@ -1,2 +1,13 @@
 # WebUntisAPI.Client
-Documentation will follow after initial publication.
+
+This .NET library allows you to connect you with a WebUntis account and load all of the data you need from there.<br>
+[![Documentation](https://img.shields.io/badge/GitHub-Documentation-red)](https://github.com/Suiram1701/WebUntisAPI.Client/wiki)
+
+### Download sources:
+- [![GitHub](https://img.shields.io/badge/GitHub-Releases-white)](https://github.com/Suiram1701/WebUntisAPI.Client/releases)<br>
+- [![NuGet](https://img.shields.io/badge/NuGet-Package-blue)](https://www.nuget.org/packages/WebUntisAPI.Client)
+
+<hr>
+
+This is an unofficial library that I created from the WebUntis API [documentation](https://untis-sr.ch/wp-content/uploads/2019/11/2018-09-20-WebUntis_JSON_RPC_API.pdf).
+