Add missing users.email unique index at database level

db/migrate/20110913195421_add_email_unique_index_to_users.rb

@@ -0,0 +1,9 @@
+class AddEmailUniqueIndexToUsers < ActiveRecord::Migration
+  def self.up
+    add_index :users, :email, :unique => true
+  end
+
+  def self.down
+    drop_index :users, :email
+  end
+end