-- Migration v16: Adsterra banners use a named placement instead of pixel offsets.
-- placement: after_topbar | after_section_1 | after_section_2 | after_section_3 | above_bottom_menu
-- Safe to run more than once. (The Adsterra admin page also adds this column automatically.)
ALTER TABLE adsterra_ads
    ADD COLUMN IF NOT EXISTS placement VARCHAR(30) NOT NULL DEFAULT 'above_bottom_menu' AFTER height;