Refactor CSV export settings and enhance file handling features with the addition of menu bar's menu items with added functionality

src/main/java/cvbuilder/model/UserGroup.java

@@ -33,4 +33,8 @@ public class UserGroup {
         }
         return users.get(index);
     }
+
+    public void clearUsers() {
+        users.clear();
+    }
 }