Add tags and rate function
Fix rate and tags bug for rich comment
Add brief comment function and tags facility
Fix comment tags and ajax refresh tags info on detail page
Add download function
Fix file download icon bug and upload default value bug
Update table brief_comments, rich_comments and literatures
Merge pull request #9 from wwzyhao/master

add the db auto backup script
rm the db/backup.sql and adjust the gitignore
adjust the layout of the detail page