Update README.md

README.md

@@ -1,3 +1,36 @@
 # Hostinger-DDNS
 
-A small piece of software for dynamically updating a DNS record for a Hostinger hosted domain.
+A small piece of software for dynamically updating a DNS record for a Hostinger hosted domain.
+
+---
+
+## Environment Variables
+
+The following environment variables must be defined in your `.env` file:
+
+- **DOMAIN**  
+  The domain you want to check and/or modify.
+
+- **SUBDOMAIN**  
+  The subdomain you want to check and/or modify.
+
+- **DNS_RECORD_TYPE**  
+  The type of record you want to change.
+
+- **TOKEN**  
+  Your Hostinger token.
+
+---
+
+## Docker Compose example
+
+```
+services:
+  hostinger-ddns:
+    build: .
+    container_name: hostinger-ddns
+    restart: unless-stopped
+    environment:
+      DOMAIN: ${DOMAIN}
+      HOSTINGER_TOKEN: ${HOSTINGER_TOKEN}
+```