Added description

packages/app/resource/locales/en_US/admin/admin.json

@@ -476,6 +476,7 @@
     "select_parent_group": "Select Parent Group",
     "release_parent_group": "Release parent group",
     "add_modal": {
+      "description": "The added user will also be added to all ancestor groups.",
       "add_user": "Add a user to the created group",
       "search_option": "Search option",
       "enable_option": "Enable {{option}}",

packages/app/resource/locales/ja_JP/admin/admin.json

@@ -475,6 +475,7 @@
     "select_parent_group": "親グループを選択",
     "release_parent_group": "親グループの解除",
     "add_modal": {
+      "description": "追加したユーザーは、祖先全てのグループにも追加されます。",
       "add_user": "グループへのユーザー追加",
       "search_option": "検索オプション",
       "enable_option": "{{option}}を有効にする",

packages/app/resource/locales/zh_CN/admin/admin.json

@@ -485,6 +485,7 @@
     "select_parent_group": "选择父组",
     "release_parent_group": "Release parent group",
     "add_modal": {
+      "description": "添加的用户也将被添加到所有祖先组。",
       "add_user": "将用户添加到创建的组",
       "search_option": "搜索选项",
       "enable_option": "启用{{option}",

packages/app/src/components/Admin/UserGroupDetail/UserGroupUserModal.jsx

@@ -23,6 +23,7 @@ class UserGroupUserModal extends React.Component {
           {t('admin:user_group_management.add_modal.add_user') }
         </ModalHeader>
         <ModalBody>
+          <p className="card well">{t('admin:user_group_management.add_modal.description')}</p>
           <div className="p-3">
             <UserGroupUserFormByInput />
           </div>