added opencollective to readme

Author: kirillmurashov

README.md

@@ -1,9 +1,18 @@
 <p align="center"><img src="http://oduvanstudio.com/vdr.gif" alt="logo"></p>
 <h1 align="center">Vue-drag-resize</h1>
 
-[![Latest Version on NPM](https://img.shields.io/npm/v/vue-drag-resize.svg?style=flat-square)](https://npmjs.com/package/vue-drag-resize)
-[![Software License](https://img.shields.io/badge/license-MIT-brightgreen.svg?style=flat-square)](LICENSE.md)
-[![npm](https://img.shields.io/npm/dt/vue-drag-resize.svg?style=flat-square)](https://www.npmjs.com/package/vue-drag-resize)
+<p align="center">
+
+  [![Latest Version on NPM](https://img.shields.io/npm/v/vue-drag-resize.svg?style=flat-square)](https://npmjs.com/package/vue-drag-resize)
+  [![Software License](https://img.shields.io/badge/license-MIT-brightgreen.svg?style=flat-square)](LICENSE.md)
+  [![npm](https://img.shields.io/npm/dt/vue-drag-resize.svg?style=flat-square)](https://www.npmjs.com/package/vue-drag-resize)
+</p>
+
+<p align="center">
+<a href="https://opencollective.com/vue-drag-resize/" target="_blank">
+  <img src="https://opencollective.com/vue-drag-resize/donate/[email protected]?color=blue" width=300 />
+</a>
+</p>
 
 > Vue Component for draggable and resizable elements.