Fixes loading with ActionController::API
Fixes loading with ActionController::API

This adds a check to see if we can call `helper` when loading the
JavascriptHelper as it's not available on ActionController::API and
causes the app to fail to load.

Fixes #40

thefrontside/stripe-rails,thefrontside/stripe-rails,thefrontside/stripe-rails,Everapps/stripe-rails,Everapps/stripe-rails,Everapps/stripe-rails