fixing the issue of user login after signing up

@akshar-raaj After the user has signed up, he was not able to log in because the user.is_active is given False. Changed it to true. If there is any reason of giving false please let me know.
@yashwanthbabu Yes, what you are doing is right. But I don't think you need to set is_active=True explicitly since is_active=True is the default. Look into this and find out if you need to set is_active=True explicitly.