Update README

Author: vberlier

README.md

@@ -1,2 +1,36 @@
-# check-commands
-Github action for checking minecraft commands.
+# Check minecraft commands
+
+> Github action to validate minecraft data packs and function files.
+
+```yml
+# .github/workflows/check-commands.yml
+name: Check commands
+on: [push]
+
+jobs:
+  check:
+    runs-on: ubuntu-latest
+    steps:
+      - uses: mcbeet/check-commands@v1
+        with:
+          source: path/to/my_data_pack
+```
+
+## Usage
+
+This github action installs [`mecha`](https://github.com/mcbeet/mecha) in an isolated virtualenv and checks your data pack and function files for errors. The inputs of the action reflect the [`mecha` command-line options](https://github.com/mcbeet/mecha#command-line-utility). Only the `source` input is required.
+
+| Input       | Optional              | Description                                                    |
+| ----------- | --------------------- | -------------------------------------------------------------- |
+| `version`   | defaults to `latest`  | The version of mecha to install                                |
+| `source`    | required              | The list of data packs, functions files or folders to validate |
+| `minecraft` | defaults to `1.17`    | The version of minecraft to use for checking commands          |
+| `log`       | defaults to `WARNING` | The output log level                                           |
+
+## Contributing
+
+Contributions are welcome. Make sure to first open an issue discussing the problem or the new feature before creating a pull request. If you find a bug please try to share a link the problematic action run.
+
+---
+
+License - [MIT](https://github.com/mcbeet/check-commands/blob/main/LICENSE)