I am curious to know how to authenticate the user with twitter and after successful login, i need the email of the user... how can it be done?
Heard that twitter doe
Just to update this issue, it is now possible (from April 2015).
You can send a support ticket to Twitter to whitelist your app to make it possible to ask for an email. Then, after an user connects their account, you need to make a GET request to verify credentials with the "include_email" option set to true.
It is explained in more detail in the second link.