Improve structure

manual/README.md

@@ -1,6 +1,6 @@
 # Introduction
 
-Seafile is an open source cloud storage system for file sync, share and document collaboration.
+Seafile is an open source cloud storage system for file sync, share and document collaboration. SeaDoc is an extension of Seafile that providing a lightweight online collaborative document feature.
 
 
 ## LICENSE

manual/contribution.md

@@ -20,7 +20,3 @@ Follow us @seafile <https://twitter.com/seafile>
 
 * Please report a bug in our forum, this is a preferred way.
 * You can also report a bug in GitHub <https://github.com/haiwen/seafile/issues?state=open>
-
-## Code Style
-
-  The source code of seafile is ISO/IEC 9899:1999 (E) (a.k.a. C99) compatible. Take a look at [code standard](develop/code_standard.md).

mkdocs.yml

@@ -71,7 +71,6 @@ nav:
     - File permission management: overview/file_permission_management.md
     - Roadmap: roadmap.md
     - Contribution: contribution.md
-    - Changelog: changelog.md
   - Setup:
     - Seafile Docker Overview: docker/seafile_docker_overview.md
     - Setup community edition with Docker: docker/deploy_seafile_with_docker.md