added event prefix

Author: Bohdan Berezhniy

Model/ResourceModel/Category/Collection.php

@@ -13,6 +13,16 @@
  */
 class Collection extends \Magento\Framework\Model\ResourceModel\Db\Collection\AbstractCollection
 {
+    /**
+     * @inheritDoc
+     */
+    protected $_eventPrefix = 'mfblog_category_collection';
+
+    /**
+     * @inheritDoc
+     */
+    protected $_eventObject = 'blog_category_collection';
+
     /**
      * @inheritDoc
      */