code: func (e *Empire) Rollback(ctx context.Context, opts RollbackOpts) (*Release, error) {
  	if err := opts.Validate(e); err != nil {
  		return nil, err
  	}
  
  	tx := e.db.Begin()
  
  	r, err := e.releases.Rollback(ctx, tx, opts)
  	if err != nil {
  		tx.Rollback()
  		return r, err
  	}
  
  	if err := tx.Commit().Error; err != nil {
  		return r, err
  	}
  
  	return r, e.PublishEvent(opts.Event())
  }
docs: // Rollback rolls an app back to a specific release version. Returns a
  // new release.