readme/usage: add section about GitHub Actions (#7)

README.md

@@ -26,6 +26,54 @@ Find further details at [dbhi.github.io/qus](https://dbhi.github.io/qus).
 
 > NOTE: Although `docker` is used in these examples, users have reported that other engines such as [podman](https://podman.io/) can also be used. See also [kata-containers/runtime#1280](https://github.com/kata-containers/runtime/issues/1280).
 
+```sh
+# docker run --rm --privileged aptman/qus -h
+Usage: register.sh [--help][--interactive][--list][--static][-- ARGS]
+
+  Wrapper around qemu-binfmt-conf.sh, to configure binfmt_misc to use qemu interpreter
+
+  -h|--help|-help:
+      display this usage
+
+  -i|--interactive|-interactive:
+      execute all the remaining args with 'sh -c', then exit
+
+  -l|--list|-list:
+      list currently registered interpreters
+
+  -s|--static|-static:
+      add '--qemu-suffix -static' to ARGS
+
+  -- ARGS:
+     arguments for qemu-binfmt-conf.sh
+
+  To register a single static target persistently, use e.g.:
+
+      register.sh -s -- -p aarch64
+
+  To remove all register interpreters and exit, use:
+
+      register.sh -- -r
+```
+
+## As a GitHub Action
+
+Run the Action without arguments for registering all the supported interpreters:
+
+```yaml
+  - uses: dbhi/qus/action@main
+```
+
+Optionally, provide an space separated list of target architectures:
+
+```yaml
+  - uses: dbhi/qus/action@main
+    with:
+      targets: arm aarch64
+```
+
+Then, execute foreign binaries and/or containers straightaway!
+
 ## Setup
 
 The recommended approach is to run the following container: