Add reference to Docker Hub image

Author: mostafa

getting-started/installation.md

@@ -58,14 +58,23 @@ sudo rpm -i gatewayd-{% github_latest_release gatewayd-io/gatewayd v %}.x86_64.r
 
 ### Docker image
 
-GatewayD is also available as a Docker image. The image is available on [GitHub Container Registry](https://ghcr.io/gatewayd-io/gatewayd:latest).
+GatewayD is also available as a Docker image. The image is available on [GitHub Container Registry](https://ghcr.io/gatewayd-io/gatewayd:latest) and [Docker Hub](https://hub.docker.com/r/gatewaydio/gatewayd).
 
 To run GatewayD using Docker, you can use the following command, considering that the `gatewayd.yaml` and `gatewayd_plugins.yaml` configuration files and plugins are located in the current working directory on the host machine. The server will be available on port `15432` on the host machine and the container will be removed after it exits.
 
 ```bash
 docker run -v ./:/opt -p 15432:15432 --rm ghcr.io/gatewayd-io/gatewayd:latest run --config /opt/gatewayd.yaml --plugins-config /opt/gatewayd_plugins.yaml
 ```
 
+The same image can be used to install plugins. The plugins will be installed in the `plugins` directory in the current working directory on the host machine.
+
+```bash
+docker run -v ./:/opt --rm ghcr.io/gatewayd-io/gatewayd:latest plugin install github.com/<organization>/<plugin-name>@<version> --plugins-config /opt/gatewayd_plugins.yaml
+```
+
+{: .note }
+> In the above examples, the image from GitHub Container Registry is used. To use the image from Docker Hub, replace `ghcr.io/gatewayd-io/gatewayd:latest` with `gatewaydio/gatewayd:latest`.
+
 ### Docker Compose
 
 For ease of use, a [docker-compose](https://github.com/gatewayd-io/gatewayd/blob/main/docker-compose.yaml) file is available. It starts two services: a PostgreSQL database and GatewayD. The server will be available on port `15432` on the host machine.