I figured I'd leave this here for those upgrading to Turbolinks 5: the easiest way to fix your code is to go from:
var ready;
ready = function() {
// Your JS here
}
$(document).ready(ready);
$(document).on('page:load', ready)
to:
var ready;
ready = function() {
// Your JS here
}
$(document).on('turbolinks:load', ready);
Reference: https://github.com/turbolinks/turbolinks/issues/9#issuecomment-184717346