add overwrite class

Change-Id: Ib5aa8123eb4dbc5ca637773ba7debaa151d9c365
diff --git a/classes/cluster/overwrite.yml b/classes/cluster/overwrite.yml
new file mode 100644
index 0000000..43de87d
--- /dev/null
+++ b/classes/cluster/overwrite.yml
@@ -0,0 +1 @@
+# this class can be used for overwriting soft parameters