docs: Add a README

Closes: jiriks74/nextcloud-ntfy.sh#5

README.md

@@ -1,3 +1,85 @@
 # nextcloud-ntfy.sh
 
-Receive Push Notifications on Android without Google services
+Are you tired of Nextcloud
+[**still not supporting notifications F-Droid**](https://github.com/nextcloud/talk-android/issues/257)?
+After 4 years I sure am!
+
+But you don't have to be because I solved it for you! Simply run this brigde,
+install install the `ntfy` app and you're done!
+
+## Features
+
+- 💻 Can be run on any machine with Python 3
+- 🌐 Support for both the official `ntfy.sh` and self-hosted instances
+- 🔒 Support for token authentication with `ntfy`
+- 🗑️ Dismiss button to remove the notification on Nextcloud too
+- 🛠️ Action buttons*
+
+> [!Note]
+> \* Action buttons currently open the browser instead of launching the correct
+>    app. I haven't found any mention of Nextcloud supporting app URLs (eg. `twitter://`)
+
+## Setup
+
+### 0. Create a new application password for your Nextcloud account
+
+This is better as if you leak you can easily remove it and no other passwords
+can be guessed from it.
+
+> [!Note]
+> If your passwords can be guessed from knowing other passwords consider
+> using a password manager and generated passwords...
+
+### 1. On the machine running the bridge
+
+1. Grab a release
+2. Create a config file: `cp config-example.json config.json`
+3. Fill out the necessary values, they should be self-explanatory:
+  - `ntfy_topic`
+  - `nextcloud_base_url`
+  - `nextcloud_username`
+  - `nextcloud_password`
+4. Start the bridge: `python3 main.py -c config.json`
+
+> [!CAUTION]
+> On `ntfy.sh` (and instances with `auth-default-access` set to `read-write`)
+> you **need** to set a secure topic id. It acts as your password so
+> **if anyone gets your topic id they can read all your notifications!**
+
+### 2. On your phone
+
+1. Install [the `ntfy.sh` app](https://f-droid.org/en/packages/io.heckel.ntfy/)
+2. Click the `+` button in the bottom right corner
+3. Input the topic you set in `config.json`
+
+### 3. Profit
+
+## How did this happen?
+
+I wanted to self-host `ntfy` so that I'd get better UnifiedPush experience
+than I had with the [Nextcloud UnifiedPush Provider](https://apps.nextcloud.com/apps/uppush)
+app. My Nextcloud instance shuts down for backups (generates a notification error in the app)
+and you have to set up redirects in order to get Matrix notifications working.
+
+So I got `ntfy` working and I saw that the documentation has
+[Integrations + community projects](https://docs.ntfy.sh/integrations/)
+section.
+
+Going through it I found this video: https://www.youtube.com/watch?v=0a6PpfN5PD8
+
+It's about a script someone created to pull notifications from Nextcloud and
+push them to `ntfy`. I found it interesting but from a quick look at the script
+it was more limited than I'd like it to be. for example the notifications
+were immediately removed from Nextcloud which I didn't like.
+
+As the script didn't have any license attached I decided to make my own
+from the ground up. Within 90 minutes I had a working prototype sending
+notifications to my phone.
+
+From there I continued my work. First I created the `Dismiss` button.
+Then I noticed that `ntfy` can create action buttons so
+I parsed Nextcloud's notification buttons into something `ntfy` can understand. 
+
+In about 4-5 hour I had basically all the features finished. Hopefully I'll
+be able to add more (like opening the Nextcloud App instead of the browser)
+but we'll see what's possible.