ALTER TABLE vitrines
  ADD COLUMN IF NOT EXISTS commentaire_publication_mode TEXT NOT NULL DEFAULT 'manual',
  ADD CONSTRAINT vitrines_commentaire_publication_mode_check
    CHECK (commentaire_publication_mode IN ('manual', 'auto'));

UPDATE vitrines
SET commentaire_publication_mode = 'manual'
WHERE commentaire_publication_mode IS NULL OR commentaire_publication_mode NOT IN ('manual', 'auto');