Merge pull request #93 from tadyjp/update_ruby_and_rails

[WIP] rubyとrailsのバージョンアップ
Merge commit 'f27cab5b50cf3ca9cad0c754aac7bd03eacf76d5' into feat/templates
Merge pull request #94 from tadyjp/feat/templates

templatesページ作成
Merge commit '92261235b3736c66592b8cdbc436cae448b2553f' into feat/visit_count
Merge pull request #100 from tadyjp/feat/visit_count

足あと機能追加
Merge commit 'f1da41880fd78cba26fcb4ce4cc0570a1a2adaf9' into feat/watch
Merge pull request #102 from tadyjp/feat/watch

watchings 追加
Merge commit '89b44582019a1351a68b5e786c1043efe12d14ea' into feat/slide_viewer