Update README about devcontainer use

Author: gbraad

README.md

@@ -22,11 +22,23 @@ You can open this repo on GitHub to read, use the GitHub Pages for a published v
 For example, it is easy to use `.` to start the GitHub Web Editor to read and edit these files.
 
 
-## Build instructions
+### Build using container
 To create the HTML output, you can use:
 
 ```
 $ podman run --rm -v $PWD:/workspace quay.io/crc-org/mdbook:0.4.43 build
 ```
 
 This will create a `book` folder that contains the output for a static webpage like GitHub Pages.
+
+
+### Devcontainer
+You can also use the devcontainer setup. This will start the generation container and allows you to use the `mdbook` command line directly from inside the editor.
+
+This can be started from CodeSpaces, VS Code or the CLI
+```shell
+$ npm install -g @devcontainers/cli
+$ devcontainer up --workspace-folder .
+```
+
+After the container has been started, you can use `mdbook build` to generate the output, and `mdbook serve` to open a preview using the forward of port 3000.