```ruby
module Detectify
  class Railtie < Rails::Railtie
    initializer 'detectify' do |app|
      app.config.middleware.use 'Detectify::Middleware'
    end
  end
end
```

Fix 'Passing strings or symbols to the middleware builder' Rails 5 deprecation warning
user
```ruby
module Detectify
  class Railtie < Rails::Railtie
    initializer 'detectify' do |app|
      app.config.middleware.use Detectify::Middleware
    end
  end
end
```
assistant