docker: add docker document.

en/docs/download.md

@@ -17,6 +17,7 @@ ddwrt|latest firmware. goto services page abd enable SmartDNS Resolver. |Demo: <
 debian|apt-get install smartdns|
 entware|ipkg update<br />ipkg install smartdns|Software source: <https://bin.entware.net/>
 MacOS|brew update<br />brew install smartdns|Software source(Rust port)：<https://github.com/mokeyish/smartdns-rs/releases/>
+docker|docker pull pymumu/smartdns | Docker image：<https://hub.docker.com/r/pymumu/smartdns>
 
 ## Download From Release Page
 

en/docs/install/docker.md

@@ -0,0 +1,26 @@
+---
+hide:
+  - toc
+---
+
+# Docker
+
+## Description
+
+SmartDNS provides a Docker image for quick installation.
+
+## Configuration
+
+Create the configuration file /etc/smartdns/smartdns.conf and add the following configuration:
+
+```
+bind [::]:53
+server 8.8.8.8
+server 1.1.1.1
+```
+
+## Run image
+
+```
+docker run -d --name smartdns --restart=always -p 53:53/udp -v /etc/smartdns:/etc/smartdns pymumu/smartdns:latest
+```

en/mkdocs.yml

@@ -77,6 +77,7 @@ nav:
     - ASUS firmware / Merlin firmware: 'install/asus.md'
     - EntWare: 'install/entware.md'
     - WSL: 'install/wsl.md'
+    - Docker: 'install/docker.md'
   - Configuration Guides:
     - Basic Configuration: 'config/basic-config.md'
     - Server Configuration: 'config/server-config.md'