修复了docker自动构建的一些问题, 更新了文档

Dockerfile

@@ -3,9 +3,9 @@ FROM mhart/alpine-node:9
 WORKDIR /app
 COPY . /app
 
-RUN    rm -rf node_modules \
-    && rm package-lock.json \
-    && npm config set registry "https://registry.npm.taobao.org/" \
+RUN    rm package-lock.json \
+    ; rm -rf node_modules \
+    ; npm config set registry "https://registry.npm.taobao.org/" \
     && npm install
 
 EXPOSE 3000