```ruby
class AddGithubIdToLabels < ActiveRecord::Migration[5.1]
  def change
    add_column :labels, :github_id, :integer
  end
end
```

Delete old, invalid labels during the migration to fix them
user
```ruby
class AddGithubIdToLabels < ActiveRecord::Migration[5.1]
  def change
    add_column :labels, :github_id, :integer
    Label.delete_all # delete previous invalid labels
  end
end
```
assistant