Sass::SyntaxError in Home#index

I have followed the instructions on how to install bootstrap. However, when I start the server I get the error Sass::SyntaxError in Home#index I have the following files.

application.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, 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 other CSS/SCSS
 * files in this directory. Styles in this file should be added after the last require_* statement.
 * It is generally better to create a new file per style scope.
 *
 *= require_tree .
 *= require_self
 */
@import "bootstrap";```

application.js:
```// This is a manifest file that'll be compiled into application.js, which will include all the files
// listed below.
//
// Any JavaScript/Coffee file within this directory, lib/assets/javascripts, or any plugin's
// vendor/assets/javascripts directory can be referenced here using a relative path.
//
// It's not advisable to add code directly here, but if you do, it'll appear at the bottom of the
// compiled file. JavaScript code in this file should be added after the last require_* statement.
//
// Read Sprockets README (https://github.com/rails/sprockets#sprockets-directives) for details
// about supported directives.
//
//= require rails-ujs
//= require_tree .
//= require jquery3
//= require popper
//= require bootstrap-sprockets```

application.html.erb
```<!DOCTYPE html>
<html>
  <head>
    <meta charset="utf-8">
    <meta http-equiv="X-UA-Compatible" content="IE=edge">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <meta name="description" content="">
    <meta name="author" content="">
    <link rel="shortcut icon" href="../../docs-assets/ico/favicon.png">

    <title>Narrow Jumbotron Template for Bootstrap</title>

    <!-- Custom styles for this template -->
    <link href="jumbotron-narrow.css" rel="stylesheet">

    <!-- Just for debugging purposes. Don't actually copy this line! -->
    <!--[if lt IE 9]><script src="../../docs-assets/js/ie8-responsive-file-warning.js"></script><![endif]-->

    <!-- HTML5 shim and Respond.js IE8 support of HTML5 elements and media queries -->
    <!--[if lt IE 9]>
      <script src="https://oss.maxcdn.com/libs/html5shiv/3.7.0/html5shiv.js"></script>
      <script src="https://oss.maxcdn.com/libs/respond.js/1.3.0/respond.min.js"></script>
    <![endif]-->
    <title>ProtestTrump</title>
    <%= csrf_meta_tags %>

    <%= stylesheet_link_tag    'application', media: 'all' %>
    <%= javascript_include_tag 'application' %>
  </head>

  <body>
    <p class="notice"><%= notice %></p>
    <p class="alert"><%= alert %></p>

    <div class="header">
      <ul class="nav nav-pills pull-right">
        <li class="active"><a href="#">Home</a></li>
        <li><a href="#">About</a></li>
        <li><a href="#">Contact</a></li>
      </ul>
      <h3 class="text-muted">Project name</h3>
    </div>

    <%= yield %>
    <div class="footer">
      <p>&copy; Company 2013</p>
    </div>
  </body>
</html>

Gemfile



git_source(:github) do |repo_name|
  repo_name = "#{repo_name}/#{repo_name}" unless repo_name.include?("/")
  "https://github.com/#{repo_name}.git"
end

# Bundle edge Rails instead: gem 'rails', github: 'rails/rails'
gem 'rails', '~> 5.1.1'
# Use postgresql as the database for Active Record
gem 'pg', '~> 0.18'
# Use Puma as the app server
gem 'puma', '~> 3.7'
# Use SCSS for stylesheets
gem 'sass-rails', '~> 5.0'
# Use Uglifier as compressor for JavaScript assets
gem 'uglifier', '>= 1.3.0'
# See https://github.com/rails/execjs#readme for more supported runtimes
# gem 'therubyracer', platforms: :ruby
gem 'rb-readline'
# Use CoffeeScript for .coffee assets and views

# Build JSON APIs with ease. Read more: https://github.com/rails/jbuilder
gem 'jbuilder', '~> 2.5'
#Authentication with Devise
gem 'devise'
# Use Redis adapter to run Action Cable in production
# gem 'redis', '~> 3.0'
# Use ActiveModel has_secure_password
# gem 'bcrypt', '~> 3.1.7'
# Bootsrap gem for front-send
gem 'bootstrap', git: 'https://github.com/twbs/bootstrap-rubygem'
# Use Capistrano for deployment
# gem 'capistrano-rails', group: :development
#paperclip for images
gem 'paperclip', '~> 5.1'

#Bootstrap JavaScript depends on jQuery. If you're using Rails 5.1+, add the jquery-rails gem to your Gemfile
gem 'jquery-rails'

group :development, :test do
  # Call 'byebug' anywhere in the code to stop execution and get a debugger console
  gem 'byebug', platforms: [:mri, :mingw, :x64_mingw]
  gem 'pry-rails', '~> 0.3.6'
  gem 'rspec-rails'
  gem 'rails-controller-testing'
  gem 'faker'
end

group :development do
  # Access an IRB console on exception pages or by using <%= console %> anywhere in the code.
  gem 'web-console', '>= 3.3.0'
  gem 'listen', '>= 3.0.5', '< 3.2'
  # Spring speeds up development by keeping your application running in the background. Read more: https://github.com/rails/spring
  gem 'spring'
  gem 'spring-watcher-listen', '~> 2.0.0'
end

# Windows does not include zoneinfo files, so bundle the tzinfo-data gem
gem 'tzinfo-data', platforms: [:mingw, :mswin, :x64_mingw, :jruby]```

twbs / bootstrap-rubygem

Sass::SyntaxError in Home#index #94