system preference

app/models/site.rb

@@ -18,7 +18,10 @@ class Site
   field :title_always_on, :type => Boolean, :default => false
   field :dashbroad_allow_visitor, :type => Boolean, :default => false
   field :mail_settings, :type => Hash
-  
+
+  field :disk_space, :type => String
+  field :system_package_info, :type => Hash,:default=>{}
+
   field :school
   field :department