Save in the database the last user that executes the command and in the ready event send a DM to him in order to notify for the restart.
Just after sending the message, delete the field (or set it to null) to not spam the person when the bot crashes or restarts naturally.
It's a good practice to notify the admin aswell all the times and send him how the bot crashed:
If the bot crashed naturally (the field is empty) just notify the admin that the bot is up with natural restart cycle.
If the bot crashed because of the restart command, notify the user that executed the command and the admin aswell with the name of the person who executed the command.
Save in the database the last user that executes the command and in the ready event send a DM to him in order to notify for the restart.
Just after sending the message, delete the field (or set it to null) to not spam the person when the bot crashes or restarts naturally.
It's a good practice to notify the admin aswell all the times and send him how the bot crashed: