docs(docker): 创建Dockerfile，新建镜像，输出hello world

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diff --git a/docs/source/docker/basic.rst b/docs/source/docker/basic.rst
@@ -11,3 +11,4 @@
    basic/[Ubuntu 16.04]安装
    basic/[Aliyun]镜像加速
    basic/[Ubuntu 16.04]可选设置
+   basic/hello-world
diff --git a/docs/source/docker/basic/hello-world.md b/docs/source/docker/basic/hello-world.md
@@ -0,0 +1,90 @@
+
+# Hello World
+
+参考：
+
+[Get Started, Part 2: Containers](https://docs.docker.com/get-started/part2/#recap-and-cheat-sheet-optional)
+
+[Best practices for writing Dockerfiles](https://docs.docker.com/develop/develop-images/dockerfile_best-practices/)
+
+`Docker`镜像由只读层组成，每个层代表一条`Dockerfile`指令。这些层是堆叠的，每一层都是前一层变化的增量
+
+下面制作最简单的`Hello World`镜像
+
+## Dockerfile
+
+新建文件夹`docker`，进入该文件后新建文件`Dockerfile`，输入以下指令
+
+```
+$ mkdir docker
+$ cd docker
+$ vim docker
+FROM ubuntu:18.04
+COPY . /app
+CMD sh /app/app.sh
+```
+
+每一条指令都会创建一个层，解释如下：
+
+* `FROM`指令创建一个层，来自于`ubuntu:18.04`镜像
+* `COPY`指令创建一个层，将当前`docker`文件夹内容复制到镜像的`/app`文件夹内
+* `CMD`指令创建一个层，运行脚本
+
+创建脚本`app.sh`，内容如下：
+
+```
+echo 'Hello World'
+```
+
+## 创建镜像
+
+输入以下指令构建镜像，指定镜像名和版本号
+
+```
+$ docker build --tag=zj:0.1.0 .
+Sending build context to Docker daemon  3.072kB
+Step 1/3 : FROM ubuntu:18.04
+18.04: Pulling from library/ubuntu
+35c102085707: Pull complete 
+251f5509d51d: Pull complete 
+8e829fe70a46: Pull complete 
+6001e1789921: Pull complete 
+Digest: sha256:d1d454df0f579c6be4d8161d227462d69e163a8ff9d20a847533989cf0c94d90
+Status: Downloaded newer image for ubuntu:18.04
+ ---> a2a15febcdf3
+Step 2/3 : COPY . /app
+ ---> 8d579b652ea1
+Step 3/3 : CMD sh /app/app.sh
+ ---> Running in 0e0f6faa5749
+Removing intermediate container 0e0f6faa5749
+ ---> 7515c3706b27
+Successfully built 7515c3706b27
+Successfully tagged zj:0.1.0
+```
+
+有上面输出日志可知，共创建了`3`个镜像，其`ID`如下：
+
+```
+a2a15febcdf3
+8d579b652ea1
+7515c3706b27
+```
+
+可通过`docker image ls`查询
+
+```
+$ docker image ls -a
+REPOSITORY          TAG                 IMAGE ID            CREATED             SIZE
+zj                  0.1.0               7515c3706b27        12 seconds ago      64.2MB
+<none>              <none>              8d579b652ea1        14 seconds ago      64.2MB
+ubuntu              18.04               a2a15febcdf3        4 weeks ago         64.2MB
+```
+
+## 运行容器
+
+使用指令`docker run`启动容器，将`Hello World`输入到当前命令行窗口
+
+```
+$ docker run zj:0.1.0
+Hello World
+```