Issue for already user exist in Database

[ankushbadlas]

Hello , I am using Angular2 at front-end and Djano Rest Framework for back-end APIs. I already have a sign up form with email field.

I tried this simple-social-auth for facebook login. I want that if email already exist in database than FbId should be update with the related exist email and login in the application but this app insert a new user every time if the email already exist.

Need a help !!