Add opencollective links

README.md

@@ -1,6 +1,6 @@
 # Upload by FriendsOfFlarum
 
-[![MIT license](https://img.shields.io/badge/license-MIT-blue.svg)](https://github.com/FriendsOfFlarum/upload/blob/master/LICENSE.md) [![Latest Stable Version](https://img.shields.io/packagist/v/fof/upload.svg)](https://packagist.org/packages/fof/upload) [![Total Downloads](https://img.shields.io/packagist/dt/fof/upload.svg)](https://packagist.org/packages/fof/upload)
+[![MIT license](https://img.shields.io/badge/license-MIT-blue.svg)](https://github.com/FriendsOfFlarum/upload/blob/master/LICENSE.md) [![Latest Stable Version](https://img.shields.io/packagist/v/fof/upload.svg)](https://packagist.org/packages/fof/upload) [![Total Downloads](https://img.shields.io/packagist/dt/fof/upload.svg)](https://packagist.org/packages/fof/upload) [![OpenCollective](https://img.shields.io/badge/opencollective-fof-blue.svg)](https://opencollective.com/fof/donate)
 
 An extension that handles file uploads intelligently for your forum.
 
@@ -90,6 +90,7 @@ The secondary is like a more detailed specification, eg `png`, `pdf` etc. These
 
 ## Links
 
+- [![OpenCollective](https://img.shields.io/badge/donate-friendsofflarum-44AEE5?style=for-the-badge&logo=open-collective)](https://opencollective.com/fof/donate)
 - [Flarum Discuss post](https://discuss.flarum.org/d/4154)
 - [Source code on GitHub](https://github.com/FriendsOfFlarum/upload)
 - [Report an issue](https://github.com/FriendsOfFlarum/upload/issues)