BUGFIX: system user needs no drafts.

lib/discourse.rb

@@ -201,8 +201,10 @@ module Discourse
     user ||= User.admins.real.order(:id).first
   end
 
+  SYSTEM_USER_ID = -1
+
   def self.system_user
-    User.find_by(id: -1)
+    User.find_by(id: SYSTEM_USER_ID)
   end
 
   def self.store

lib/post_revisor.rb

@@ -25,7 +25,7 @@ class PostRevisor
     update_topic_excerpt
     post_process_post
     update_topic_word_counts
-    @post.advance_draft_sequence
+    @post.advance_draft_sequence unless editor.id == Discourse::SYSTEM_USER_ID
     PostAlerter.new.after_save_post(@post)
     publish_revision