Allow creatig FridgeProductLine from fridge form

templates/fridge/single.html.twig

@@ -2,4 +2,35 @@
 
 {% block body %}
     {{ form(form) }}
+    <button type="button" class="btn btn-primary add_item_link" data-collection-holder-id="fridge_productLines">Add product</button>
+{% endblock %}
+
+{% block javascripts %}
+    {{ parent() }}
+    <script>
+      const addFormToCollection = (e) => {
+        const collectionHolder = document.querySelector('#' + e.currentTarget.dataset.collectionHolderId);
+        console.log(collectionHolder);
+
+        const item = document.createElement('div');
+
+        item.innerHTML = collectionHolder
+            .dataset
+            .prototype
+            .replace(
+                /__name__label__/g,
+                collectionHolder.children.length
+            )
+            .replace(
+                /__name__/g,
+                collectionHolder.children.length
+            );
+
+        collectionHolder.appendChild(item);
+      };
+
+      document
+          .querySelectorAll('.add_item_link')
+          .forEach(btn => btn.addEventListener("click", addFormToCollection));
+    </script>
 {% endblock %}