Allow optional trailing comma in tuple parser
diff --git a/src/derive.rs b/src/derive.rs
index 3bf125c..ecef776 100644
--- a/src/derive.rs
+++ b/src/derive.rs
@@ -186,7 +186,7 @@
 
     named!(data_union -> (Option<WhereClause>, FieldsNamed), tuple!(
         option!(syn!(WhereClause)),
-        syn!(FieldsNamed)
+        syn!(FieldsNamed),
     ));
 }