feat: 耕作履歴ページ作成（#112） (#177)

#112 現在ページの表示を太く

#112 完了

Co-authored-by: miteruzo <miteruzo@naver.com>
Reviewed-on: #177

frontend/src/components/TopNav.tsx

@@ -30,6 +30,7 @@ export default (({ user }: Props) => {
       { name: '広場', to: '/posts', subMenu: [
 	  { name: '一覧', to: '/posts' },
 	  { name: '投稿追加', to: '/posts/new' },
+	  { name: '耕作履歴', to: '/posts/changes' },
 	  { name: 'ヘルプ', to: '/wiki/ヘルプ:広場' }] },
       { name: 'タグ', to: '/tags', subMenu: [
 	  { name: 'タグ一覧', to: '/tags', visible: false },