docs(doc): update docs

CHANGELOG.md

@@ -1,9 +1,12 @@
-Change Log
-=
+# Changelog
 
-2019-10-28:
+## [Unreleased] 2019-10-29
 
-* update: add source update fetch control by `/set` command (usually used when source updating paused by reached 100 error when getting update data)
-* update: merge `/set` command's response message template to a function for more struct
+### Added
+- source update fetch control by `/set` command (usually used when source updating paused by reached 100 error when 
+getting update data)
+- export feeds
+
+### Changed
+- merge `/set` command's response message template to a function for more struct
 
-***

README.md

@@ -7,7 +7,7 @@
 
 DEMO: [https://t.me/rssflowbot](https://t.me/rssflowbot)  
 [问题反馈群组](https://t.me/joinchat/FJ-cikd-yN1Bf1SxWbAKjw)
-[Change Log](ChangeLog.md)
+[Change Log](CHANGELOG.md)
 
 <img src="https://github.com/rssflow/img/raw/master/images/rssflow_demo.gif" width = "300"/>
 
@@ -93,7 +93,8 @@ curl https://api.telegra.ph/createAccount?short_name=flowerss&author_name=flower
 /unsub [url] 取消订阅（url 为可选）
 /list 查看当前订阅
 /set 设置订阅
-/import 导入OPML文件
+/import 导入 OPML 文件
+/export 导出 OPML 文件
 /help 帮助
 ```