-- Adds the Trash / restore feature for deleted documents (admin-only
-- view, restore, and — deliberately — no way to permanently delete a
-- document at all; see api/documents.php). Run once via phpMyAdmin ->
-- Import, or:
--   mysql -u user -p dbname < sql/migration_004_trash.sql

ALTER TABLE documents
    ADD COLUMN deleted_by INT NULL AFTER deleted,
    ADD COLUMN deleted_at DATETIME NULL AFTER deleted_by,
    ADD CONSTRAINT fk_documents_deleted_by FOREIGN KEY (deleted_by) REFERENCES users(id);