Fix #2771: Approving deleted image doesn't create mod action.

app/models/post.rb

@@ -327,6 +327,10 @@ class Post < ActiveRecord::Base
 
       PostApproval.create(user_id: CurrentUser.id, post_id: id)
 
+      if is_deleted_was == true
+        ModAction.create(:description => "undeleted post ##{id}")
+      end
+
       save!
     end