Выпадающее меню Codeigniter и Bootstrap

<li class='nav-item dropdown'>
                <a class='nav-link dropdown-toggle' href = "" role='button' id = "dropdownCadastro"
                   data-toggle='dropdown' aria-haspopup = "true" aria-expanded = "false">
                    Projeto
                </a>
                <div class = "dropdown-menu shadow border-0" aria-labelledby = "dropdownCadastro">
                <a class = "dropdown-item js-scroll-trigger" href='<?php echo base_url('projeto');?> '>Cadastrar Projeto</a>
               <a class = "dropdown-item js-scroll-trigger" href='<?php echo base_url('avaliacao');?> '>Avaliar Projeto</a>
                <a class = "dropdown-item js-scroll-trigger" href='<?php echo base_url('consultarProjetoServidor');?> '>Consultar Projeto</a>
                </div>
            </li>

  <link  rel = "stylesheet" href = "<?php echo base_url('assets/vendor/bootstrap/css/bootstrap.min.css') ?>" >
    <link  rel = "stylesheet" href = "<?php echo base_url('fonts/fontawesome-free/css/all.min.css') ?>" >
    <!-- Custom fonts for this template -->
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    <link  rel = "stylesheet" href = "https://fonts.googleapis.com/css?family=Lato:100,100i,300,300i,400,400i,700,700i,900,900i">
    <link rel = "stylesheet" href = "https://use.fontawesome.com/releases/v5.7.0/css/all.css"
          integrity = "sha384-lZN37f5QGtY3VHgisS14W3ExzMWZxybE1SJSEsQp9S+oqd12jhcu+A56Ebc1zFSJ" crossorigin = "anonymous">

    <!-- Custom styles for this template -->
    <link rel = "stylesheet" href = "<?php echo base_url('assets/css/one-page-wonder.min.css') ?>" >

<script src = "https://ajax.googleapis.com/ajax/libs/jquery/1.11.1/jquery.min.js"></script>
<script type = "text/javascript" src = "https://maxcdn.bootstrapcdn.com/bootstrap/4.0.0/js/bootstrap.min.js"></script>