Create Ruby on Rails application from bootstrap theme

application.js

//= require rails-ujs
//= require activestorage
//= require jquery
//= require jquery_ujs
//= require popper
//= require bootstrap
//= require aos.js
//= require clipboard.js
//= require jquery.fancybox.min.js
//= require flickity.pkgd.min.js
//= require ion.rangeSlider.min.js
//= require isotope.pkgd.min.js
//= require jarallax.min.js
//= require jarallax-video.min.js
//= require jarallax-element.min.js
//= require jquery.countdown.min.js
//= require plyr.polyfilled.min.js
//= require prism.js
//= require scrollMonitor.js
//= require smooth-scroll.polyfills.min.js
//= require twitterFetcher_min.js
//= require typed.min.js
//= require theme.js
//= require_self

window.addEventListener("load", function () {
  document.querySelector('body').classList.add('loaded');
});

Gemfile

# add this gems to Gemfile
gem 'bootstrap', '~> 4.3.1'
gem 'jquery-rails'
gem 'popper_js', '~> 1.14.5'

parse_template.rake

namespace :parse_template do
  task :start do
    # get array of paths to html files (pages)
    pages = Dir.glob("#{Rails.root}/tmp/BootstrapThemeOne/pages/**/*.html")

    # goes trough each page path
    pages.each do |page_path|
      # find name of page 
      page_name = page_path.split('/').last.split('.').first
      
      # open this page and parse with Nokogiri gem (includede in Rails by default)
      parse_page = Nokogiri::HTML(open(page_path))

      # take all html inside body tag expect common like header nav, footer
      page_inner_content = parse_page.css('body > *:not(footer#footer):not(script):not(header.navbar-container):not(.loader):not(.back-to-top)')

      # create app/views/pages/page_name.html.erb file and write content there  
      File.open("#{Rails.root}/app/views/pages/#{page_name.underscore}.html.erb", 'w') { |f|
        f.write(page_inner_content.to_html)
      }
    end
  end
end

This is rake task parse bootstrap theme into Rails app views