reference.md in profitbricks-sdk-ruby-1.1.0

- old
+ new

@@ -203,10 +203,10 @@
 
     volume = datacenter.get_volume(volume_id)
 
 Create a volume:
 
-    volume = datacenter.create_volume(name: "volume1", size: 20)
+    volume = datacenter.create_volume(name: "volume1", size: 20, type: "SSD")
 
 Update a volume:
 
     volume.update(description: "My Volume", size: 40)