Create OpenID authentications from existing users
user
```ruby
class CreateOpenIdAuthenticationsFromExistingUsers < ActiveRecord::Migration
  def up
    say_with_time "Creating OpenID authentications for existing OpenID users" do
      User.where(:using_openid => true).find_each do |user|
        user.authentications.create(
          :uid => user.login,
          :provider => 'open_id',
          :name => user.fullname,
          :email => user.email
        )
      end
    end
  end
end
```
assistant