Why is Bootstrap's dropdown not working in Rails?

Question

Ruby on Rails

_header.html.erb

<header class="navbar navbar-fixed-top navbar-inverse">
<div class="container">
  <%= link_to "sample app", root_path, id: "logo" %>
    <nav>
      <ul class="nav navbar-nav navbar-right">
        <li><%= link_to "Home", root_path %></li>
        <li><%= link_to "Help", help_path %></li>
        <% if logged_in? %>
          <li><%= link_to "Users", '#' %></li>
          <li class="dropdown">
          <a href="#" class="dropdown-toggle" data-toggle="dropdown">
            Account <b class="caret"></b>
          </a>
        <ul class="dropdown-menu">
          <li><%= link_to "Profile", current_user %></li>
          <li><%= link_to "Settings", '#' %></li>
          <li class="divider"></li>
          <li>
            <%= link_to "Log out", logout_path, method: "delete" %>
          </li>
        </ul>
      </li>
    <% else %>
      <li><%= link_to "Log in", login_path %></li>
    <% end %>
      </ul>
    </nav>
  </div>
</header>

application.js

//= require jquery
//= require jquery_ujs
//= require bootstrap
//= requireturbolinks
//= require_tree

connected in scss

@import "bootstrap-sprockets";
@import "bootstrap";

Answer 1

sprockets and webpacker are just add-ons that solve a bunch of problems when working with assets.
When something goes wrong, the algorithm is as follows:
1. Create a clean prototype on HTML / CSS / JS + the necessary libs
2. Use the browser's dev tools to see what doesn't match what the rails generates: library version ( gems and packages may be different from examples), DOM path, generated scripts, javascript order, and so on. You need to understand what exactly is the problem.
3. Read the doc for a specific tool to understand how to make it work the way you want. Well, or ask here already a more specific question. Like here is such and such a code, you need to generate code such and such, and another is generated