Added imports for milestone dispatcher routes

app/assets/javascripts/dispatcher.js

@@ -198,18 +198,28 @@ import { fetchCommitMergeRequests } from './commit_merge_requests';
             .catch(fail);
           break;
         case 'projects:milestones:new':
+        case 'projects:milestones:create':
+          import('./pages/projects/milestones/new')
+            .then(callDefault)
+            .catch(fail);
+          break;
         case 'projects:milestones:edit':
         case 'projects:milestones:update':
-          new ZenMode();
-          new DueDateSelectors();
-          new GLForm($('.milestone-form'), true);
+          import('./pages/projects/milestones/edit')
+            .then(callDefault)
+            .catch(fail);
           break;
         case 'groups:milestones:new':
+        case 'groups:milestones:create':
+          import('./pages/groups/milestones/new')
+            .then(callDefault)
+            .catch(fail);
+          break;
         case 'groups:milestones:edit':
         case 'groups:milestones:update':
-          new ZenMode();
-          new DueDateSelectors();
-          new GLForm($('.milestone-form'), false);
+          import('./pages/groups/milestones/edit')
+            .then(callDefault)
+            .catch(fail);
           break;
         case 'projects:compare:show':
           new Diff();

app/assets/javascripts/pages/groups/milestones/edit/index.js

+import initForm from '../../../../shared/milestones/form';
+
+export default () => initForm();

app/assets/javascripts/pages/groups/milestones/new/index.js

+import initForm from '../../../../shared/milestones/form';
+
+export default () => initForm();

app/assets/javascripts/pages/projects/milestones/edit/index.js

+import initForm from '../../../../shared/milestones/form';
+
+export default () => initForm();

app/assets/javascripts/pages/projects/milestones/new/index.js

+import initForm from '../../../../shared/milestones/form';
+
+export default () => initForm();

app/assets/javascripts/shared/milestones/form.js

+import ZenMode from '../../zen_mode';
+import DueDateSelectors from '../../due_date_select';
+import GLForm from '../../gl_form';
+
+export default () => {
+  new ZenMode(); // eslint-disable-line no-new
+  new DueDateSelectors(); // eslint-disable-line no-new
+  new GLForm($('.milestone-form'), true); // eslint-disable-line no-new
+};