Update README.md

Author: RomanTsukanov

README.md

@@ -1,3 +1,3 @@
-# getting-started-with-dropdownbox
+# getting-started-with-dropdownbutton
 
-This repository stores the source code for the [Getting Started with DropDownButton](https://js.devexpress.com/Documentation/Guide/Widgets/DropDownButton/Getting_Started_with_DropDownButton/) tutorial.
+This repository stores the source code for the [Getting Started with DropDownButton](https://js.devexpress.com/Documentation/Guide/Widgets/DropDownButton/Getting_Started_with_DropDownButton/) tutorial.