app/assets/javascripts/active_admin.js
//= require active_admin/base
//= require just_datetime_picker/nested_form_workaround
//= require select2
$(document).ready(function() {
$('.need-user-autocomplete').select2({
dropdownAutoWidth : true,
width: 'auto',
ajax: {
url: '/api/user/autocomplete',
cache: false
}
});
})