Add dns instructions

docs/PRODUCTION.md

@@ -86,9 +86,75 @@ docker compose -f docker-compose.prod.yml -f docker-compose.caddy.yml ps
 ## Prerequisites
 
 -   A Linux server with Docker and Docker Compose installed.
--   Two registered domain names (e.g., `kaboot.example.com` and `auth.example.com`).
--   DNS A records pointing both domains to your server.
--   A Google Gemini API key.
+-   A registered domain name (e.g., `example.com`).
+-   DNS A records pointing your domains to your server (see below).
+-   A Google Gemini API key (optional, for AI quiz generation).
+
+## DNS Configuration
+
+You need two DNS records pointing to your server's IP address. You can use either:
+- **Subdomains**: `kaboot.example.com` + `auth.example.com` (recommended)
+- **Apex + subdomain**: `example.com` + `auth.example.com`
+
+### Finding Your Server's IP
+
+```bash
+# On your server, run:
+curl -4 ifconfig.me
+```
+
+### Namecheap Setup
+
+1. Log in to [Namecheap](https://www.namecheap.com/) and go to **Domain List**
+2. Click **Manage** next to your domain
+3. Go to the **Advanced DNS** tab
+4. Add the following **A Records**:
+
+| Type | Host | Value | TTL |
+|------|------|-------|-----|
+| A Record | `kaboot` | `YOUR_SERVER_IP` | Automatic |
+| A Record | `auth` | `YOUR_SERVER_IP` | Automatic |
+
+> **Note**: The "Host" field is the subdomain prefix only. For `kaboot.example.com`, enter just `kaboot`.
+
+### Cloudflare Setup
+
+1. Log in to [Cloudflare](https://dash.cloudflare.com/) and select your domain
+2. Go to **DNS** → **Records**
+3. Click **Add record** and create:
+
+| Type | Name | IPv4 address | Proxy status |
+|------|------|--------------|--------------|
+| A | `kaboot` | `YOUR_SERVER_IP` | DNS only (gray cloud) |
+| A | `auth` | `YOUR_SERVER_IP` | DNS only (gray cloud) |
+
+> **Important**: Set proxy status to "DNS only" (gray cloud) for both records. Caddy handles SSL, and Cloudflare's proxy can interfere with certificate generation.
+
+### Other Providers (GoDaddy, Google Domains, etc.)
+
+The process is similar for most providers:
+
+1. Find the **DNS Management** or **DNS Settings** section
+2. Add two **A Records**:
+   - **Name/Host**: `kaboot` → **Value/Points to**: `YOUR_SERVER_IP`
+   - **Name/Host**: `auth` → **Value/Points to**: `YOUR_SERVER_IP`
+3. Set TTL to automatic or 300 seconds
+
+### Verify DNS Propagation
+
+After adding records, verify they're working (may take 5-30 minutes):
+
+```bash
+# Check if DNS resolves to your server
+dig kaboot.example.com +short
+dig auth.example.com +short
+
+# Or use nslookup
+nslookup kaboot.example.com
+nslookup auth.example.com
+```
+
+Both should return your server's IP address. You can also use [dnschecker.org](https://dnschecker.org/) to verify global propagation.
 
 ## Architecture Overview