FEATURE: Change user groups in bulk via admin

app/assets/javascripts/admin/controllers/admin-groups-bulk.js.es6

@@ -0,0 +1,34 @@
+import computed from 'ember-addons/ember-computed-decorators';
+import { popupAjaxError } from 'discourse/lib/ajax-error';
+
+export default Ember.Controller.extend({
+  users: null,
+  groupId: null,
+  saving: false,
+
+  @computed('saving', 'users', 'groupId')
+  buttonDisabled(saving, users, groupId) {
+    return saving || !groupId || !users || !users.length;
+  },
+
+  actions: {
+    addToGroup() {
+      if (this.get('saving')) { return; }
+
+      const users = this.get('users').split("\n")
+                                      .uniq()
+                                      .reject(x => x.length === 0);
+
+      this.set('saving', true);
+      Discourse.ajax('/admin/groups/bulk', {
+        data: { users, group_id: this.get('groupId') },
+        method: 'PUT'
+      }).then(() => {
+        this.transitionToRoute('adminGroups.bulkComplete');
+      }).catch(popupAjaxError).finally(() => {
+        this.set('saving', false);
+      });
+
+    }
+  }
+});