Kentico CMS allows you to modify some of the system tables and enhance them with custom attributes. You can edit them in Site Manager -> Development -> System tables.
When you add a new column to the user profile, it is available on the Custom fields tab of the User properties dialog.
Always allow empty values
When creating a new empty field in a system table, it is highly recommended that you always allow empty values in the newly created field, so that the system procedures and existing dialogs keep working.
|•||If you would like to learn how to add custom data to all documents, please refer to the Custom document data topic.|
Page url: http://devnet.kentico.com/docs/5_5r2/devguide/index.html?system_tables_overview.htm