Update docker

server/docker.md

-## Setup Docker on CensOS
+## Setup Docker on CentOS
 
-### Install
+### 1. Install
 Require Kernel version: >= 2.6.32-431.
 
 Use `uname -a` to check current kernel version.
@@ -13,7 +13,7 @@ wget https://get.docker.com/builds/Linux/x86_64/docker-latest -O docker
 chmod +x docker
 ```
 
-### Run docker daemon
+### 2. Run docker daemon
 
 Must run as `root`
 
@@ -22,7 +22,7 @@ sudo su -
 docker -d &
 ```
 
-### Assign non-root access to docker daemon
+### 3. Assign non-root access to docker daemon
 
 For example, we need to give `docker` access to user `ventura`