Logout

この issue には説明がありません。

The issue title 'Logout' suggests adding a logout feature to the Elm application. Start by examining the existing authentication flow in the codebase, likely in files handling user sessions or authentication state. Look for any login-related modules or state management to understand how to implement a logout action. Determine what 'done' looks like by checking if there are tests for authentication or if a logout button needs to be added to the UI.

索引モデルが issue の本文から書いたものです。