application.css.scss

@import "bootstrap";

body {
  padding-top: 80px;
}

application.haml

!!!
%html
  %head
    %meta{:charset => "utf-8"}
    %title Sinatra, sprockets, compass, bootstrap-sass playing together
    %link{ rel: 'stylesheet', href: stylesheet_path('application.css') }/

  %body
    .container
      = yield

config.ru

require './swc_application'

use Rack::Cache, verbose: false

map SwcApplication.assets_prefix do
  run SwcApplication.assets
end

map '/' do
  run SwcApplication
end

Gemfile

source :rubygems

gem 'shotgun', :group=>:development

gem 'rack-cache'
gem 'sinatra', :require => 'sinatra/base'
gem 'sinatra-support'

gem 'haml'

gem 'sprockets'
gem 'sprockets-helpers'
gem 'sprockets-sass'

gem 'compass'
gem 'bootstrap-sass'
gem 'coffee-script'

gem 'uglifier'

swc_application.rb

require 'bundler'
Bundler.require

# Helpers
require './lib/render_partial'

class SwcApplication < Sinatra::Base
  set :root,          File.dirname(__FILE__)
  set :assets,        Sprockets::Environment.new(root)
  set :precompile,    [ /\w+\.(?!js|css).+/, /application.(css|js)$/ ]
  set :assets_prefix, '/assets'
  set :digest_assets, false
  set(:assets_path)   { File.join public_folder, assets_prefix }

  configure do
    # Setup Sprockets
    %w{javascripts stylesheets images}.each do |type|
      assets.append_path "assets/#{type}"
      assets.append_path Compass::Frameworks['bootstrap'].templates_directory + "/../vendor/assets/#{type}"
    end
    assets.append_path 'assets/font'

    # Configure Sprockets::Helpers (if necessary)
    Sprockets::Helpers.configure do |config|
      config.environment = assets
      config.prefix      = assets_prefix
      config.digest      = digest_assets
      config.public_path = public_folder
    end
    Sprockets::Sass.add_sass_functions = false

    set :haml, { :format => :html5 }
  end

  before do
    expires 500, :public, :must_revalidate
  end

  get '/' do
    haml :index, :layout => :'layouts/application'
  end

  helpers do
    include Sprockets::Helpers
    include RenderPartial
  end

end