RailsにBootstrapを導入後、ハンバーガーメニューが開かない現象について

前提・実現したいこと

rails(5.2)にBootstrap(4.4)を導入し、ハンバーガーメニュー付きのナビバーを作成したい。

発生している問題・エラーメッセージ

ナビバーのハンバーガーメニューが開かない。
（画面サイズが小さくなるとナビバーのメニューがハンバーガーに収納はされるがクリックして開けない。）
デザインは反映されているのでJavaScriptに関する部分が動作してないと考えています。

該当のソースコード

application.html.erb

html
1<!DOCTYPE html>
2<html>
3  <head>
4    <title>AgriHelp</title>
5    <%= csrf_meta_tags %>
6    <%= csp_meta_tag %>
7    <%= stylesheet_link_tag    'application', media: 'all' %>
8    <%= javascript_include_tag 'application' %>
9  </head>
10
11  <body>
12
13    <nav class="navbar navbar-expand-lg navbar-dark" style="background-color: #544a2e;">
14      <a class="navbar-brand" href="#">Agri help</a>
15      <button class="navbar-toggler" type="button" data-toggle="collapse" data-target="#navbarSupportedContent" aria-controls="navbarSupportedContent" aria-expanded="false" aria-label="Toggle navigation">
16        <span class="navbar-toggler-icon"></span>
17      </button>      
18      <div class="collapse navbar-collapse" id="navbarNav">
19        <ul class="navbar-nav">
20          <li class="nav-item active">
21            <a class="nav-link" href="#">Home <span class="sr-only">(current)</span></a>
22          </li>
23          <li class="nav-item">
24            <a class="nav-link" href="#">会員登録</a>
25          </li>
26          <li class="nav-item">
27            <a class="nav-link" href="#">ログイン</a>
28          </li>
29          <li class="nav-item">
30            <a class="nav-link" href="#">マイページ</a>
31          </li>
32          <li class="nav-item">
33            <a class="nav-link" href="#">助っ人を探す</a>
34          </li>
35          <li class="nav-item">
36            <a class="nav-link" href="#">チャット</a>
37          </li>
38          <li class="nav-item">
39            <a class="nav-link" href="#">ログアウト</a>
40          </li>
41        </ul>
42      </div>
43    </nav>
44
45    <%= yield %>
46  </body>
47</html>
48

application.js

js
1// This is a manifest file that'll be compiled into application.js, which will include all the files
2// listed below.
3//
4// Any JavaScript/Coffee file within this directory, lib/assets/javascripts, or any plugin's
5// vendor/assets/javascripts directory can be referenced here using a relative path.
6//
7// It's not advisable to add code directly here, but if you do, it'll appear at the bottom of the
8// compiled file. JavaScript code in this file should be added after the last require_* statement.
9//
10// Read Sprockets README (https://github.com/rails/sprockets#sprockets-directives) for details
11// about supported directives.
12//
13
14//= require jquery
15//= require popper
16//= require bootstrap
17
18//= require rails-ujs
19//= require activestorage
20//= require_tree .

application.scss

scss
1*
2 * This is a manifest file that'll be compiled into application.css, which will include all the files
3 * listed below.
4 *
5 * Any CSS and SCSS file within this directory, lib/assets/stylesheets, or any plugin's
6 * vendor/assets/stylesheets directory can be referenced here using a relative path.
7 *
8 * You're free to add application-wide styles to this file and they'll appear at the bottom of the
9 * compiled file so the styles you add here take precedence over styles defined in any other CSS/SCSS
10 * files in this directory. Styles in this file should be added after the last require_* statement.
11 * It is generally better to create a new file per style scope.
12 *
13 */
14 @import "bootstrap";