add modaction helper

app/logical/moderator/tag_batch_change.rb

@@ -12,7 +12,7 @@ module Moderator
 
       CurrentUser.without_safe_mode do
         CurrentUser.scoped(updater, updater_ip_addr) do
-          ModAction.create(:description => "processed mass update: #{antecedent} -> #{consequent}")
+          ModAction.log("processed mass update: #{antecedent} -> #{consequent}")
 
           ::Post.tag_match(antecedent).where("true /* Moderator::TagBatchChange#perform */").find_each do |post|
             post.reload

app/logical/user_deletion.rb

@@ -30,7 +30,7 @@ class UserDeletion
 private
   
   def create_mod_action
-    ModAction.create(:description => "user ##{user.id} deleted")
+    ModAction.log("user ##{user.id} deleted")
   end
 
   def clear_tag_subscriptions