view _comment has a link to destroy the comment.  #14

No controller code, yet.

Signed-off-by: ataka <masayuki.ataka@gmail.com>
comments_controller delete 'destroy comment'.  #14

Not ensure that comment is not destroyed,
when its post is deleted.

Signed-off-by: ataka <masayuki.ataka@gmail.com>
Ensure that delete comments when deleting parent post.  close #14

Signed-off-by: ataka <masayuki.ataka@gmail.com>