Replace link to CoderDojo Kata with self-hosted page ##61
Replace link to CoderDojo Kata with self-hosted page ##61

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