added notice about csrf

Author: execut

CHANGELOG.md

@@ -10,3 +10,8 @@ Version 1.1.0 December 09, 2016
 ---------------------------
 
   - Request parameter "ids" change support
+
+Version 1.1.1 March 10, 2017
+---------------------------
+
+  - Added CSRF notice in documentaion

DOCUMENTATION.md

@@ -58,3 +58,6 @@ DeleteMultipleAction Class
 [renderTagAttributes()]:http://www.yiiframework.com/doc-2.0/yii-helpers-basehtml.html#renderTagAttributes()-detail
 [dropDownList()]:http://www.yiiframework.com/doc-2.0/yii-helpers-basehtml.html#dropDownList()-detail
 [t()]:http://www.yiiframework.com/doc-2.0/yii-baseyii.html#t()-detail
+
+### CSRF validation
+For enable CSRF validation make sure you have ```<?= Html::csrfMetaTags() ?>``` in main layout.