Require jquery.turbolinks in all JS specs

Side-effect: This simplifies the requiresInput handler

app/assets/javascripts/behaviors/requires_input.js.coffee

@@ -34,6 +34,5 @@ $.fn.requiresInput = ->
 
   $form.on 'change input', fieldSelector, requireInput
 
-# Triggered on standard document `ready` and on Turbolinks `page:load` events
-$(document).on 'ready page:load', ->
+$ ->
   $('form.js-requires-input').requiresInput()

spec/javascripts/spec_helper.coffee

@@ -9,6 +9,7 @@
 # require the specific files that are being used in the spec that tests them.
 
 #= require jquery
+#= require jquery.turbolinks
 #= require bootstrap
 #= require underscore