Add Caddy setup (wow, that's an easy config)

Signed-off-by: Odyssey <hi@odyssey346.dev>

README.md

@@ -55,6 +55,13 @@ go build -o gothub
 
 If you don't want to use port 3000 for GotHub, set the GOTHUB_PORT environment variable to the port you want to use.
 
+### Web server configuration (Caddy)
+We recommend Caddy for the web server, as it provides automatic HTTPS, HTTP/3 and is easy to setup.
+```caddyfile
+gothub.example.com {
+    reverse_proxy localhost:3000
+}
+```
 
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