Add link to donations.

README.md

@@ -2,6 +2,8 @@
 
 [![Wekan chat][vanila_badge]][vanila_chat]
 
+[Donations][donations]
+
 2017-02-08 News: All of Wefork is now merged and moved back to official
 Wekan. Wefork will not accept any new issues and pull requests.
 All development happens on Wekan.
@@ -185,3 +187,4 @@ with [Meteor](https://www.meteor.com).
 [autoinstall]: https://github.com/wefork/wekan-autoinstall
 [autoinstall_issue]: https://github.com/anselal/wekan/issues/18
 [dev_docs]: https://github.com/wekan/wekan/wiki/Developer-Documentation
+[donations]: http://www.xet7.org/wekan