Braintree cancel subscription

Hi,

So, I implemented the braintree payment processing and everything works perfect. Now the only issue I am having is if I user cancels their subscription through my web application everything works fine, but if I cancel the subscription or braintree cancels their subscription through my braintree dashboard it does not update my users cancellation through my web application. I figure this is a problem because if a user does not pay their monthly bill be default braintree cancels their subscription due to failure of payment and users will continue to use my service for free.

class SubscriptionsController < ApplicationController
    before_action :authenticate_user!, except: [:new]
    before_action :redirect_to_signup, only: [:new]

  def show

  end

  def new

  end

  def create
    if current_user.braintree_id?
      customer = Braintree::Customer.find(current_user.braintree_id)
    else
      result = Braintree::Customer.create(
        email: current_user.email,
        payment_method_nonce: params[:payment_method_nonce]
      )
      customer = result.customer
      current_user.update(braintree_id: customer.id)
    end

    result = Braintree::Subscription.create(
      payment_method_token: customer.payment_methods.find{ |pm| pm.default? }.token,
      plan_id: '25pm'
    )
    current_user.update(braintree_subscription_id: result.subscription.id)

    redirect_to root_path, notice: "You have been subscribed"
  end

  def destroy
    customer = Braintree::Customer.find(current_user.braintree_id)
    Braintree::Subscription.cancel(current_user.braintree_subscription_id)
    current_user.update(braintree_subscription_id: nil)

    redirect_to root_path, notice: "Your Subscription has been canceled"
  end

  private

  def redirect_to_signup
    if !user_signed_in?
        session["user_return_to"] = new_subscription_path
        redirect_to new_user_registration_path
    end
  end

end