Squashed 'ryosuke/' content from commit 79f13e9

git-subtree-dir: ryosuke
git-subtree-split: 79f13e9d54cbce8a50ff39fecbc5d0deb37bd6e1
Merge commit '5c276f6eace80231c8e50be3b34f960ac023e422' as 'ryosuke'