Notify function in App.js

This issue should be resolved by creating notify that:

Input
1) Message
2) Has Error (default is false)

Use toast, ToastContainer from react-toastify to notify the user the message using if else based on has error param

Output
Toast Message/Error

Start in App.js and inspect how notifications are currently handled. Use the requested message and has-error inputs with react-toastify's toast and ToastContainer, then verify that success and error messages produce the corresponding toast output.

索引モデルが issue の本文から書いたものです。