add domain link: Prevent double add and fix modal operation.

Partial #775

app/javascript/domain_links.js

@@ -1,8 +1,4 @@
-import { onLoad } from './util';
-
-onLoad(() => {
-  $('.domain-link-form').on('ajax:success', (ev, data) => {
-    $('.domain-links-list').append(data);
-    $(ev.target).parents('.modal').modal('close');
-  });
+$(document).on('ajax:success', '#new_domain_link', (ev, data) => {
+  $('.domain-links-list').append(data);
+  $(ev.target).parents('.modal').modal('hide');
 });

app/javascript/packs/application.js

@@ -118,7 +118,9 @@ const metasmoke = window.metasmoke = {
     initFormParamCleanups: () => {
       const formParameterCleanups = [];
 
-      $(document.body).on('submit', 'form', ev => {
+      // This excludes data-remote, because other JavaScript creates the POST, so this code
+      // results in a duplicated POST being sent.
+      $(document.body).on('submit', 'form:not([data-remote="true"])', ev => {
         const tgt = $(ev.target);
         if (formParameterCleanups.indexOf(tgt[0]) === -1) {
           ev.preventDefault();