Add example

README.md

@@ -1,3 +1,40 @@
 # cookidoo-shopping-advanced
 
-A Cookidoo Shopping List Scraper and Parser for better results. It can unify and merge all ingredients by different rule sets.
+A Cookidoo Shopping List Scraper and Parser for better results. It can unify and merge all ingredients by different rule sets.
+
+## Example
+
+```php
+// use ...
+$config = require('config.php');
+
+$cookidooScraper = new CookidooScraper();
+$cookidooScraper->login(
+    $config['account']['username'], 
+    $config['account']['password']
+);
+
+$list = $cookidooScraper->getShopptingList();
+
+$ruleApplicator = new RuleApplicator();
+$ruleApplicator->applyRules(
+    $list, 
+    [ 
+        new Rules\Omit(),
+        new Rules\Simplify(),
+        new Rules\MergeSame(),
+    ]
+);
+
+$categorizedList = $list->getByCategory();
+// ...
+```
+
+## Caching
+
+You can cache the shopping list as a json file:
+```php
+file_put_contents('./list.json', $list->toJson());
+
+$list = ShoppingList::fromJson(file_get_contents('./list.json'));
+```