app/assets/javascripts/relationship.js
$(document).ready(function() {
if($('.user').length > 0){
$(document).on('ajax:error', function (e, xhr) {
if(xhr.status === 422){
$('.message').remove();
$('.toolbar').before('<section class="message"><div class="alert">'+ xhr.responseText+'</div></section>');
}
});
}
});