don't rely on journal record id to find predecessor and use version instead

app/models/journal.rb

@@ -187,10 +187,10 @@ class Journal < ActiveRecord::Base
   end
 
   def predecessor
-    @predecessor ||= Journal.where("journable_type = ? AND journable_id = ? AND id < ?",
-                                   journable_type, journable_id, id)
+    @predecessor ||= Journal.where("journable_type = ? AND journable_id = ? AND version < ?",
+                                   journable_type, journable_id, version)
                             .order("version DESC")
-                            .first
+                            .limit(1).first
   end
 
   def journalized_object_type