Bootstrap styling not being applied to Rails page - ruby-on-rails

Question

I'm new to Rails, so have been following an online video tutorial building a project.
I've been trying to add Bootstrap, but even after
Adding the Gem,
Doing a bundle install,
Restarting the mysql server, and
Adding the scss #bootsrap import to the application.css.scss file,
It's still not pulling though to my index page.
Is there something I'm missing?
Here's my application.css.scss
/*
* This is a manifest file that'll be compiled into application.css, which will include all the files
* listed below.
*
* Any CSS and SCSS file within this directory, lib/assets/stylesheets, vendor/assets/stylesheets,
* or any plugin's vendor/assets/stylesheets directory can be referenced here using a relative path.
*
* You're free to add application-wide styles to this file and they'll appear at the bottom of the
* compiled file so the styles you add here take precedence over styles defined in any styles
* defined in the other CSS/SCSS files in this directory. It is generally better to create a new
* file per style scope.
*
*= require_self
*/
// Custom bootstrap variables must be set or imported before bootstrap itself.
#import "bootstrap-sprockets";
#import "bootstrap";
Here's my gem file:
source 'https://rubygems.org'
gem 'rails', '4.2.6'
gem 'sqlite3'
gem 'simple_form', '>= 3.2.1'
gem 'bootstrap-sass', '~> 3.3.6'
gem 'sass-rails', '>= 3.2'
gem 'uglifier', '>= 1.3.0'
gem 'coffee-rails', '~> 4.1.0'
gem 'jquery-rails'
gem 'turbolinks'
gem 'jbuilder', '~> 2.0'
gem 'sdoc', '~> 0.4.0', group: :doc
group :development, :test do
gem 'byebug'
end
group :development do
gem 'web-console', '~> 2.0'
end
gem 'tzinfo-data', platforms: [:mingw, :mswin, :x64_mingw, :jruby]
Thanks!

Answer 1

Please add in your application.html.erb
<%= stylesheet_link_tag 'application', media: 'all', 'data-turbolinks-track' => true %>
<%= javascript_include_tag 'application', 'data-turbolinks-track' => true %>
And add in your application.css
#import "bootstrap-sprockets";
#import "bootstrap";
#import 'bootstrap/theme';