Add Radarr Cloudron app packaging

- Add CloudronManifest.json with app configuration
- Add Dockerfile for building Radarr image
- Add start.sh script to launch Radarr
- Add icon.png for app icon
- Update README.md with installation and usage instructions

README.md

@@ -1,3 +1,56 @@
 # cloudron-radarr
 
-Movie organizer/manager for usenet and torrent users. Packaged for Cloudron
+Radarr is a movie collection manager for Usenet and BitTorrent users. Packaged for Cloudron.
+
+## Prerequisites
+
+You need to install Cloudron CLI: [here](https://docs.cloudron.io/packaging/cli/).
+After you need to connect the CLI to your cloudron instance.
+
+## Building the Docker Image
+
+To build the Docker image:
+
+```bash
+docker build -t yourusername/cloudron-radarr:1.0.0 .
+```
+
+## Installing on Cloudron
+
+To install the app on Cloudron, you need to be in this directory (so Cloudron CLI can read `CloudronManifest.json`):
+
+```bash
+cloudron install --image yourusername/cloudron-radarr:1.0.0
+```
+
+Or if you've pushed to a registry:
+
+```bash
+cloudron install --image registry.example.com/yourusername/cloudron-radarr:1.0.0
+```
+
+## Cloudron Volumes
+
+You will likely need to create volumes for:
+- Download folder (for completed downloads)
+- Movies library folder (for your movie collection)
+
+Here is the guide to create cloudron volumes: [guide](https://docs.cloudron.io/volumes/#add).
+
+**I recommend choosing "Filesystem" mount type when you create the volumes.**
+
+⚠️ **You need to physically create the folder on host before, cloudron can't create one for you.**
+
+To connect a volume to the app, go to the app's settings, then "storage" tab and "mount" options on the right panel.
+
+## Configuration
+
+Radarr will store its configuration in `/app/data/config/` which is automatically managed by Cloudron's localstorage addon.
+
+## Updating
+
+To update Radarr, rebuild the Docker image with a new version tag and update the app through Cloudron's interface or CLI.
+
+## License
+
+MIT License - see LICENSE file for details.