update readme

README.md

@@ -1,8 +1,45 @@
-```
-npm install
-npm run start
-```
+# Redirector
+
+Simple redirection service.
+Runs on Node and uses [Hono](https://hono.dev).
+
+Can be adapted to run on Bun, Cloudflare Workers, or any other serverless platform.
+
+Available as a [Docker image](https://hub.docker.com/r/nzambello/redirector).
+
+## Usage
 
 ```
-open http://localhost:3000
+yarn install
+REDIRECT_URL=https://nzambello.dev PERMANENT=true yarn start
+```
+
+Then, open http://localhost:7878/ in your browser.
+
+```
+open http://localhost:7878
+```
+
+and you will be redirected to `REDIRECT_URL` from your env.
+
+## Configuration
+
+It loads configuration from environment variables:
+
+- `REDIRECT_URL`: the url to redirect to
+- `PERMANENT`: if true, it will return a 301 status code, otherwise 302
+
+## Docker compose example
+
+```yaml
+version: "3.8"
+
+services:
+  redirector:
+    image: nzambello/redirector:latest
+    environment:
+      - REDIRECT_URL=https://nzambello.dev
+      - PERMANENT=true
+    ports:
+      - 7878:7878
 ```