ENV file instructions unclear

[ben05allen]

It's not clear in README.md that the tenant ID needs to be appended to the authority, easy fix as below. Happy to submit a PR too.

Refer to the image above to set the values for Client and Tenant ID in the following ENV.

CLIENTID=[client id]
AUTHORITY=https://login.microsoftonline.com/[tenant id]
REDIRECT_URI=http:https://localhost:3000
POSTLOGOUT_REDIRECT_URI=http:https://localhost:3000

[Akash52]

@ben05allen Thank you for your suggestion