time for a new version (#1451)

Author: xinyis991105

config/application.rb

@@ -109,6 +109,6 @@ class Application < Rails::Application
     config.middleware.use Rack::Attack
 
     # site version
-    config.site_version = "2.7.0"
+    config.site_version = "2.8.0"
   end
 end