ALTER TABLE courses
  ADD COLUMN slug VARCHAR(191) NULL DEFAULT NULL,
  ADD COLUMN category VARCHAR(100) NOT NULL DEFAULT 'Course',
  ADD COLUMN level VARCHAR(100) NOT NULL DEFAULT 'All levels',
  ADD COLUMN accent CHAR(7) NOT NULL DEFAULT '#421181',
  ADD COLUMN outcomes LONGTEXT NULL;

UPDATE courses SET slug = CONCAT('course-', id) WHERE slug IS NULL OR slug = '';

CREATE UNIQUE INDEX uq_courses_slug ON courses (slug);