diff --git a/Gemfile_rails4.lock b/Gemfile_rails4.lock
index 128c950f045..b25cdf8d328 100644
--- a/Gemfile_rails4.lock
+++ b/Gemfile_rails4.lock
@@ -517,6 +517,7 @@ DEPENDENCIES
   qunit-rails
   rack-cors
   rack-mini-profiler!
+  rack-protection
   rails!
   rails-observers
   rails_multisite!
diff --git a/db/migrate/20121123054127_make_post_number_distinct.rb b/db/migrate/20121123054127_make_post_number_distinct.rb
index 4bca13b7898..f6b4805a77d 100644
--- a/db/migrate/20121123054127_make_post_number_distinct.rb
+++ b/db/migrate/20121123054127_make_post_number_distinct.rb
@@ -20,8 +20,11 @@ from
 ) as X
 where calc <> p.post_number and X.id = p.id')
 
-    remove_index :posts, :forum_thread_id_and_post_number
-    add_index :posts, [:topic_id, :post_number], unique: true
+    # automagically does this
+    unless rails4?
+      remove_index :posts, :forum_thread_id_and_post_number
+      add_index :posts, [:topic_id, :post_number], unique: true
+    end
   end
 
   def down