Kindly go to the Setting > Configuration > General Setting
in that you will find General setting for Authentication
Use external authentication providers, sign in with google, facebook
check it and click on apply & log out with your account & refresh the page.
now again go to the Setting > Configuration > General Setting
you will find
Allow users to sign in with Facebook
mark it checked.
create a application on facebook from https://developers.facebook.com/apps and get the app ID.
paste the your application id to textbox you will see after text: Now copy paste the client_id here:
and then click on apply.
that's it. next time when you login you can see the link to login with facebook.
Hope this helps.
Login through social sites can be done easily in Odoo. Regarding Facebook, You don't need any custom addons. Just setup a facebook app from developer platform, configure your URI details there and paste the app id in Odoo Oauth provider form. You can get proper instructions from here Note that Facebook has revised their API terms and they are forcing the login over https through 'Enforce HTTPS' for newly creating apps. If you want to use this app in public (for large number of users), You have to keep it as LIVE after the submission to Facebook team.