CREATE TABLE IF NOT EXISTS attachments (
    id BIGINT GENERATED ALWAYS AS IDENTITY PRIMARY KEY,
    user_id BIGINT NOT NULL,
    comment_id BIGINT NOT NULL,
    created_at TIMESTAMPTZ NOT NULL DEFAULT now(),
    -- stored in file storage by attachment id
    CONSTRAINT fk_user_id FOREIGN KEY (user_id) REFERENCES users(id) ON DELETE CASCADE,
    CONSTRAINT fk_comment_id FOREIGN KEY (comment_id) REFERENCES ticket_comments(id) ON DELETE CASCADE
)