Update offline read

Update offline read  (#312)

docker-compose.yml

@@ -1,6 +1,8 @@
 version: "3"
 services:
 
+  # $ docker-compose up server => up a server，Only Support Linux or macOS
+
   server:
     image: yeasy/docker_practice:latest
     ports:
@@ -9,14 +11,7 @@ services:
       - ./:/srv/gitbook-src
     command: server
 
-  windows:
-    image: nginx:alpine
-    volumes:
-      - ./:/srv/www
-      - .travis/conf.d:/etc/nginx/conf.d
-    ports:
-      - 4000:4000
-    command: ["nginx", "-c", "/etc/nginx/conf.d/nginx.conf", "-g", "daemon off;"]
+  # $ docker-compose up build => build gitbook
 
   build:
     image: yeasy/docker_practice:latest
@@ -24,6 +19,18 @@ services:
       - ./:/srv/gitbook-src
     command: build
 
+  # $ docker run -it --rm -p 4000:80 dockerpracticecn/docker_practice
+
+  # $ docker up offline
+
+  offline:
+    # this image build by travis ci
+    image: dockerpracticecn/docker_practice
+    ports:
+      - 4000:80
+
+  # developer test docker image
+
   development:
     build: ./.travis
     image: yeasy/docker_practice:latest