Bugfix: use Hash#merge! instead of Hash#merge
Bugfix: use Hash#merge! instead of Hash#merge

params.merge don't modify self so `link` in JSON data will be ignored, so Item.create raises ActiveRecord::StatementInvalid.

id774/fastladder,onk/fastladder,onk/fastladder,ykzts/fastladder,fastladder/fastladder,toshimaru/fastladder,onk/fastladder,ykzts/fastladder,toshimaru/fastladder,ykzts/fastladder,fastladder/fastladder,toshimaru/fastladder,id774/fastladder,id774/fastladder,fastladder/fastladder