Added backers and sponsors on the README

README.md

@@ -1,5 +1,7 @@
 File Manager
 ===========
+[![Backers on Open Collective](https://opencollective.com/openintents/backers/badge.svg)](#backers)
+ [![Sponsors on Open Collective](https://opencollective.com/openintents/sponsors/badge.svg)](#sponsors) 
 
 OpenIntents file manager, see [the website](http://www.openintents.org/en/filemanager)
 
@@ -27,3 +29,33 @@ Download
 
 * [F-Droid](https://f-droid.org/repository/browse/?fdid=org.openintents.filemanager)
 * [Google Play Store](https://play.google.com/store/apps/details?id=org.openintents.filemanager)
+
+## Contributors
+
+This project exists thanks to all the people who contribute. [[Contribute](CONTRIBUTING.md)].
+<a href="graphs/contributors"><img src="https://opencollective.com/openintents/contributors.svg?width=890&button=false" /></a>
+
+
+## Backers
+
+Thank you to all our backers! 🙏 [[Become a backer](https://opencollective.com/openintents#backer)]
+
+<a href="https://opencollective.com/openintents#backers" target="_blank"><img src="https://opencollective.com/openintents/backers.svg?width=890"></a>
+
+
+## Sponsors
+
+Support this project by becoming a sponsor. Your logo will show up here with a link to your website. [[Become a sponsor](https://opencollective.com/openintents#sponsor)]
+
+<a href="https://opencollective.com/openintents/sponsor/0/website" target="_blank"><img src="https://opencollective.com/openintents/sponsor/0/avatar.svg"></a>
+<a href="https://opencollective.com/openintents/sponsor/1/website" target="_blank"><img src="https://opencollective.com/openintents/sponsor/1/avatar.svg"></a>
+<a href="https://opencollective.com/openintents/sponsor/2/website" target="_blank"><img src="https://opencollective.com/openintents/sponsor/2/avatar.svg"></a>
+<a href="https://opencollective.com/openintents/sponsor/3/website" target="_blank"><img src="https://opencollective.com/openintents/sponsor/3/avatar.svg"></a>
+<a href="https://opencollective.com/openintents/sponsor/4/website" target="_blank"><img src="https://opencollective.com/openintents/sponsor/4/avatar.svg"></a>
+<a href="https://opencollective.com/openintents/sponsor/5/website" target="_blank"><img src="https://opencollective.com/openintents/sponsor/5/avatar.svg"></a>
+<a href="https://opencollective.com/openintents/sponsor/6/website" target="_blank"><img src="https://opencollective.com/openintents/sponsor/6/avatar.svg"></a>
+<a href="https://opencollective.com/openintents/sponsor/7/website" target="_blank"><img src="https://opencollective.com/openintents/sponsor/7/avatar.svg"></a>
+<a href="https://opencollective.com/openintents/sponsor/8/website" target="_blank"><img src="https://opencollective.com/openintents/sponsor/8/avatar.svg"></a>
+<a href="https://opencollective.com/openintents/sponsor/9/website" target="_blank"><img src="https://opencollective.com/openintents/sponsor/9/avatar.svg"></a>
+
+