Add docker installation.

cli/index.md

@@ -151,6 +151,16 @@ Packages can also be found for [download](https://dist.duck.sh/).
 ::::
 :::::
 
+### Docker Image
+
+_Cyberduck CLI_ is available as a [Docker Image](https://github.com/iterate-ch/cyberduck/pkgs/container/cyberduck). Install from the command line with
+
+    docker pull ghcr.io/iterate-ch/cyberduck:latest
+
+### GitHub Action
+
+_[Cyberduck CLI GitHub Action](https://github.com/iterate-ch/cyberduck-cli-action)_ is available for [GitHub Actions](https://github.com/features/actions). It runs Cyberduck CLI within a docker container. Refer to [Use Cyberduck CLI GitHub Action](../tutorials/cli_github_action.md).
+
 ## Usage
 
 `Usage:duck [options...]`