Refactor

Use "File.extname" in "File#ext" method.
Merge pull request #79 from kaosf/fix-file-ext

Uploader::File#ext を File.extname を使うようリファクタリング
fix css: .field_with_errors
Fix JS a little
Merge pull request #80 from kaosf/fix-js

Fix JS a little
move permit_params :released
assets:precompile
fix ads module
fix: ads banner parts
release_plan addon
fix cms/ja.yml
fix Cms::Addon::Release