Register template handler after app initializers have set config (#6)

This waits to register the erb handler until after the initializers have
run and had a chance to set the configuration.

Fixes #1 and alternative to #2

Author: excid3

lib/reactionview/railtie.rb

@@ -16,7 +16,7 @@ class Railtie < Rails::Railtie
       end
     end
 
-    initializer "reactionview.configure_erb_handler" do
+    config.after_initialize do
       ActiveSupport.on_load(:action_view) do
         if ReActionView.config.intercept_erb
           ActionView::Template.register_template_handler :erb, ReActionView::Template::Handlers::Herb