Add reference to Apollo Client developer extension

.env.example

@@ -0,0 +1 @@
+NODE_ENV="development"

README.md

@@ -12,7 +12,11 @@
 - [wp-graphql-woocommerce](https://github.com/wp-graphql/wp-graphql-woocommerce) Adds Woocommerce functionality to a WPGraphQL schema.
 - [algolia-woo-indexer](https://github.com/w3bdesign/algolia-woo-indexer) Sends WooCommerce products to Algolia.
 
-1. Make sure WooCommerce has some products already or import some sample products
+2. For debugging and testing, install either https://addons.mozilla.org/en-US/firefox/addon/apollo-developer-tools/ (Firefox) or https://chrome.google.com/webstore/detail/apollo-client-developer-t/jdkknkkbebbapilgoeccciglkfbmbnfm (Chrome) depending on your browser. 
+
+Rename .env.example to .env so the Apollo debugger will correctly load. It will not load if the NODE_ENV variable is not correctly set. 
+
+3. Make sure WooCommerce has some products already or import some sample products
 
    The WooCommerce sample products CSV file is available at `wp-content/plugins/woocommerce/sample-data/sample_products.csv` or [Sample products](sample_products/)
 

utils/apollo/ApolloClient.js

@@ -23,6 +23,7 @@ import { WOO_CONFIG } from 'utils/config/nextConfig';
 export const middleware = new ApolloLink((operation, forward) => {
   /**
    * If session data exist in local storage, set value as session header.
+   * Here we also delete the session if it is older than 24 hours
    */
   const session = process.browser ? localStorage.getItem('woo-session') : null;
   const sessionAge = process.browser