FIX: correct old username index

(in some cases search was not finding accounts)

app/models/search_observer.rb

@@ -66,7 +66,7 @@ class SearchObserver < ActiveRecord::Observer
       end
     end
     if obj.class == User && (obj.username_changed? || obj.name_changed?)
-      SearchObserver.update_users_index(obj.id, obj.username, obj.name)
+      SearchObserver.update_users_index(obj.id, obj.username_lower, obj.name.downcase)
     end
 
     if obj.class == Topic && obj.title_changed?

db/migrate/20141118011735_correct_username_search.rb

@@ -0,0 +1,11 @@
+class CorrectUsernameSearch < ActiveRecord::Migration
+  def up
+    execute "update user_search_data
+              set search_data = TO_TSVECTOR('simple', username_lower || ' ' || lower(name))
+            from users
+            where users.id = user_search_data.user_id"
+  end
+
+  def down
+  end
+end