[Add proper variables for unjoin card](https://github.com/wekan/wekan/pull/2313).

Thanks to chotaire.

CHANGELOG.md

@@ -1,3 +1,10 @@
+# Upcoming Wekan release
+
+This release fixes the following bugs:
+
+- [Add proper variables for unjoin card](https://github.com/wekan/wekan/pull/2313).
+  Thanks to chotaire.
+
 # v2.57 2019-04-02 Wekan release
 
 This release fixes the following bugs, thanks to justinr1234: