Update structure

SUMMARY.md

@@ -79,11 +79,11 @@
   * [示例四：学历认证](app_dev/chaincode_example04.md)
   * [示例五：社区能源共享](app_dev/chaincode_example05.md)
   * [小结](app_dev/summary.md)
-* [Fabric 架构与设计](fabric_arch/README.md)
-  * [简介](fabric_arch/intro.md)
-  * [架构设计](fabric_arch/design.md)
-  * [消息协议](fabric_arch/protocol.md)
-  * [小结](fabric_arch/summary.md)
+* [Fabric 架构与设计](fabric_design/README.md)
+  * [简介](fabric_design/intro.md)
+  * [架构设计](fabric_design/design.md)
+  * [消息协议](fabric_design/protocol.md)
+  * [小结](fabric_design/summary.md)
 * [区块链即服务](baas/README.md)
   * [Bluemix BaaS](baas/bluemix.md)
   * [超能 BaaS](baas/sv.md)