Add documentation

README.md

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 # inotify-base
-Slim debian image with inotify pre-installed
+
+A slim image allowing for quick and easy webhooking on configuration/other file
+changes.
+
+This can be used as a sidecar container in Kubernetes/Docker/container based
+applications to trigger certain HTTP webhook/other commands upon a change to a
+mounted file/folder.
+
+## Configuration
+
+| Variable                  | Description                                                                                                                                                      | Default        |
+|---------------------------|------------------------------------------------------------------------------------------------------------------------------------------------------------------|----------------|
+| `INOTIFY_HOOK_SCRIPT`     | The executable to run on a change, as a path mounted on the filesystem                                                                                           | None           |
+| `INOTIFY_WATCH_EVENTS`    | The types of events to listen for as a comma separated list, for example `delete,move`. A full list of events is available on the [inotifywait manpage][manpage] | All events     |
+| `INOTIFY_WATCH_DIRECTORY` | The directory to watch for changes in, all subdirectories are recursively watched.                                                                               | `/opt/monitor` |
+| `INOTIFY_HOOK_DELAY`      | A delay (in seconds) to wait before executing a hook, also acts as a debounce cooldown to prevent multiple events within a timespan                              | No delay       |
+
+[manpage]: https://linux.die.net/man/1/inotifywait
+
+It is recommended to mount your `INOTIFY_HOOK_SCRIPT` in a location that is not
+used by any other aspect of the container, for example, mounting to
+`/opt/owl-corp/` and using `/opt/owl-corp/hook.sh` as your `INOTIFY_HOOK_SCRIPT`
+option.
+
+## Usage
+
+A Docker compose file using this image might look like the following:
+
+``` yaml
+services:
+  notifier:
+    image: "ghcr.io/owl-corp/inotify-base:latest"
+    volumes:
+    - type: bind
+      source: ./config
+      target: /opt/monitor
+    - type: bind
+      source: ./scripts
+      target: /opt/owl-corp
+    environment:
+      INOTIFY_HOOK_SCRIPT: /opt/owl-corp/script.sh
+```
+
+This will watch for all configuration changes in the local filesystem `config`
+directory and execute the `script.sh` file in the local `scripts` directory.
+
+## License
+
+MIT License.