I recently updated to Bootstrap 4.0.0, I'm running Rails 5.1.5 and I installed BS as specified in the README in their github.
Furthermore it's been added to package.json for yarn.
In gemfile : gem 'bootstrap', '~> 4.0' gem 'jquery-rails'
In package.json : "bootstrap": "^4.0.0", "popper.js": "^1.12.9", "jquery": "^3.3.0"
I set it in my application.scss : @import "bootstrap";
My app/assets/javascripts/application.js:
//= require rails-ujs
//= require jquery3
//= require popper
//= require bootstrap-sprockets
//= require bootstrap
//= require_tree .
Now I trying a basic exemple from an online doc :
<div class="dropdown">
<button class="btn btn-primary dropdown-toggle" type="button" id="about-us" data-toggle="dropdown" aria-haspopup="true" aria-expanded="false">
About Us
</button>
<div class="dropdown-menu" aria-labelledby="about-us">
<a class="dropdown-item" href="#">Our Story</a>
<a class="dropdown-item" href="#">Our Team</a>
<a class="dropdown-item" href="#">Contact Us</a>
</div>
</div>
The problem is that when I click the button, the menu appears, but if I click again it doesn't goes back, and after that I can't click it anymore, it's like frozen.
Try just to include bootstrap script files directly in your HTML file, it should do the thing and I think it shouldn't be a problem for you.
You can get them here https://getbootstrap.com/docs/4.0/getting-started/introduction/
It should like this:
Here is a working JSFiddle with those files: https://jsfiddle.net/c5bnsrsy/1/