Install foodcritic gem to check the recipes.

Foodcritic is used to check the recipes' validity,
but Gemfile does not list it.

In order to check the recipes' validity,
make sure to install foodcritic.

This commit fixes #210.
Merge branch 'id/210' into dev
Test only recipe differences.

- Before

Test the differences from HEAD~3 to HEAD.
This specification can include the difference to the latest commit.
It's quite overhead.

- After

Test only the recipe differences from the latest commit ID to HEAD.

This commit fixes #209.
Merge branch 'id/209' into dev