post
https://app.asana.com/api/1.0/tables//addCustomFieldSetting
Required scope: tables:write
Custom fields are associated with tables by way of custom field settings. This method creates a setting for the table.
Unlike projects and portfolios, tables only support custom fields that are global (published) to the workspace. Reusing a non-global custom field, or creating a new field inline that isn't global, will fail with a 403 Forbidden error.