Discord Redirect URI Configuration Instruction is Missing

[parkerhutcheson]

Description:
There is a crucial step missing in the documentation for setting up Discord OAuth with next-auth. Without configuring the Redirect URI in the Discord Developer Console, the authentication process will fail.

Steps to Reproduce:

Follow the current documentation to set up Discord OAuth with next-auth.
Attempt to authenticate with Discord.
Observe the failure.
Expected Behavior:
The documentation should include a step to configure the Redirect URI in the Discord Developer Console.

Proposed Solution:
Add the following step to the documentation:

Configure Redirect URI in Discord Developer Console:
Go to the Discord Developer Portal.
Select your application.
Navigate to the "OAuth2" section.
Add http://localhost:3000/api/auth/callback/discord to the Redirects field.
Save the changes.
Without this configuration, the authentication will not work, leading to potential confusion for developers following the setup guide.

Additional Context:
This step is essential for the OAuth flow to complete successfully. Including it in the documentation will help prevent authentication errors and improve the overall developer experience.