track initializer

@nevir 

```
Slow requires:
    104.08  ./config/initializers/zz.rb
    164.72  sprockets.environment
    179.55  :eager_load!
    345.62  ./config/initializers/middleware.rb
    440.37  ./config/initializers/time_zones.rb
    713.10  :build_middleware_stack
   1736.88  ./config/initializers/i18n.rb
   1972.12  :set_routes_reloader_hook
   4359.59  :load_config_initializers
```