Add doc: How to update dojos_id_seq to the existing maximum
Add doc: How to update dojos_id_seq to the existing maximum

coderdojo-japan/coderdojo.jp,yasslab/coderdojo.jp,coderdojo-japan/coderdojo.jp,coderdojo-japan/coderdojo.jp,yasslab/coderdojo.jp,yasslab/coderdojo.jp,coderdojo-japan/coderdojo.jp