def twitter
        @user = User.from_omniauth(request.env["omniauth.auth"])
        if @user.persisted?
          flash[:notice] = I18n.t "devise.omniauth_callbacks.success", :kind => "Twitter"
          sign_in_and_redirect @user, :event => :authentication
        else
          session["devise.twitter_data"] = request.env["omniauth.auth"].except("extra")
          redirect_to twitter_register_path
        end
    end

def self.from_omniauth(auth)
    where(provider: auth.provider, uid: auth.uid).first_or_create do |user|
      user.provider = auth.provider
      user.uid = auth.uid
      user.email = auth.info.email
      user.name = auth.info.name
      user.password = Devise.friendly_token[0,20]
    end
end