add user signatures

migrations.lua

@@ -68,4 +68,9 @@ return {
     schema.add_column("post_history", "original_markup", types.text{null = false})
     schema.add_column("post_history", "markup_language", types.text{default = "babycode"})
   end,
+  
+  [10] = function ()
+    schema.add_column("users", "signature_original_markup", types.text{default = ""})
+    schema.add_column("users", "signature_rendered", types.text{default = ""})
+  end,
 }