I have tried every tutorial and every guide but I am not able to integrate bootstrap in my rails app
I have tried bootstrap-sass gem, bootstrap CDN, bootstrap gem

Ruby on Rails version 
5.2.0
Ruby version 2.2.6

EXACTLY FOLLOWED THESE TUTORIALS AND HAVE ACHIEVED 0 RESULTS:

for bootstrap sass 
<https://github.com/twbs/bootstrap-sass>

for bootstrap <https://github.com/twbs/bootstrap>

tried using bootstrap CDN
<https://www.bootstrapcdn.com/>

I have been stuck on this for weeks, tried solving it on my own, followed many blog posts and StackOverflow answers and tried everything.
Is it a problem with rails 5.2 version? or my operating system windows 10
is there a gem missing in my gem file?

EDIT: I can run bundle install successfully, adding CDN in my head tag in application.html.erb does not solve my problem 
The problem I am facing is that I cant use bootstrap no matter what method I try

GEM FILE :

```
source 'https://rubygems.org'
git_source(:github) { |repo| "https://github.com/#{repo}.git" }

ruby '2.2.6'

gem 'rails', '~> 5.2.0'

gem 'sqlite3'

gem 'puma', '~> 3.11'

gem 'coffee-script-source', '1.8.0'

gem 'bootstrap-sass', '~> 3.3.7'

gem 'sass-rails', '~> 5.0'

gem 'jquery-rails'

gem 'uglifier', '>= 1.3.0'

gem 'duktape'

gem 'coffee-rails', '~> 4.2'

gem 'turbolinks', '~> 5'

gem 'jbuilder', '~> 2.5'

gem 'bootsnap', '>= 1.1.0', require: false

```