Added a Mail permisssion target

ref #124

src/models/enums/PermissionTargets.ts

@@ -15,5 +15,6 @@ export enum PermissionTarget {
     STATION = 'STATION',
     CARD = 'CARD',
     DONATION = 'DONATION',
-    CONTACT = 'CONTACT'
+    CONTACT = 'CONTACT',
+    MAIL = 'MAIL'
 }