ActiveRecord::RecordNotUnique (PG::UniqueViolation: ERROR:  duplicate key value violates unique constraint "index_users_on_email"

def self.find_for_oauth(auth, signed_in_resource = nil)


identity = Identity.find_for_oauth(auth)
user = signed_in_resource ? signed_in_resource : identity.user



if user.nil?



  email = auth.info.email
  user = User.where(:email => email).first

  unless self.where(email: auth.info.email).exists?


    if user.nil?

        user = User.new(
          profile_img: auth.info.image,

          password: Devise.friendly_token[0,20]
        )
      user.save!      #Error message said this line is problem
    end
  end
end

  if identity.user != user
    identity.user = user
    identity.save!
  end
  user



end