feat: add subscription cancel endpoint

app/controllers/subscriptions_controller.rb

@@ -0,0 +1,26 @@
+# frozen_string_literal: true
+
+class SubscriptionsController < ApplicationController
+  before_action :set_user, only: %i[destroy]
+
+  # DELETE /user/:user_id/subscription
+  # DELETE /user/:user_id/subscription.json
+  def destroy
+    head :not_authorized unless current_user == @user
+
+    subscription = @user.subscription
+
+    subscription.active = false
+    if subscription.save
+      head :ok
+    else
+      head :bad_request
+    end
+  end
+
+  private
+
+  def set_user
+    @user = User.find(params[:user_id])
+  end
+end

config/routes.rb

@@ -21,6 +21,7 @@
   resources :users, only: %i[show new edit update create destroy] do
     resource :streak, only: %i[show]
     resources :cards, only: %i[index destroy]
+    resource :subscription, only: %i[destroy]
   end
 
   get '/login' => 'sessions#login'