docs: add more to the readme

the current readme does not provide information regarding documentation,
feedback and contribution guide. This commit adds these crucial information
to make the repo more developer friendly

Signed-off-by: jiaxiao zhou <[email protected]>

Author: Mossaka

README.md

@@ -1,5 +1,17 @@
 # Containerd Shim Spin
 
-This project aims to provide the containerd shim implementation for [Spin](https://developer.fermyon.com/spin), which enables running Spin workloads on Kubernetes via [runwasi](https://github.com/deislabs/runwasi). This means that by installing this shim onto Kubernetes nodes, we can add a [runtime class](https://kubernetes.io/docs/concepts/containers/runtime-class/) to Kubernetes and schedule Spin workloads on those nodes. Your Spin apps can act just like container workloads!
+This project aims to provide the [containerd shim](https://github.com/containerd/containerd/blob/main/core/runtime/v2/README.md#runtime-shim) implementation for [Spin](https://developer.fermyon.com/spin), which enables running Spin workloads on Kubernetes via [runwasi](https://github.com/deislabs/runwasi). This means that by installing this shim onto Kubernetes nodes, we can add a [runtime class](https://kubernetes.io/docs/concepts/containers/runtime-class/) to Kubernetes and schedule Spin workloads on those nodes. Your Spin apps can act just like container workloads!
 
 [runwasi](https://github.com/deislabs/runwasi) is a project that aims to run WASI workloads managed by [containerd](https://containerd.io/).
+
+## Documentation
+
+To learn more about the Containerd Shim Spin, please visit [the official Containerd Shim Spin documentation](https://www.spinkube.dev/docs/containerd-shim-spin/).
+
+## Feedback
+
+For questions or support, please visit our [Slack channel](https://cloud-native.slack.com/archives/C06PC7JA1EE): #spinkube. 
+
+## Contributing
+
+If you would like to contribute, please visit this [contributing](https://www.spinkube.dev/docs/containerd-shim-spin/contributing/) page.