feat: Added README

Author: julian-siebert

README.md

@@ -0,0 +1,31 @@
+
+# Agones Java Client SDK
+
+**Third-party Agones Java Client SDK supporting all stable features and beta counters**
+
+- For [Agones](https://agones.dev)
+
+## Development
+
+Full development setup available as [Development Container](https://containers.dev/).
+Please use it for being able to tell "It works on my machine".
+
+**Docker is required to be installed on your machine!**
+
+### IntelliJ IDEA
+
+- Open IntelliJ (Welcome screen)
+- Navigate to `Remote Development` - `Dev Containers`
+- Press `New Dev Container`
+- Select `From VCS Project`
+- Select and connect with `Docker`
+- Select `IntelliJ IDEA`
+- Enter `Git Repository`: `https://github.com/o7studios/agones-java-sdk`
+- Select `Detection for devcontainer.json file` `Automatic`
+- Press `Build Container and Continue`
+
+### Development Container Issues
+
+If you encounter an issue with setting up a development container, please
+try to rebuild it first before opening a GitHub Issue. It's not uncommon
+that some issues may fix themselves after a fresh container rebuild.