app_templates_controller.rb

#as seen in https://github.com/mooktakim/heroku_deployment
class AppTemplatesController < ApplicationController
  def app
    render :inline => "SUCCESS", :layout => 'master'
  end
  
  def cms
    render :inline => "SUCCESS", :layout => 'cms_admin'
  end
end

cache_assets.rake

desc "cache assets"
task :cache_assets => :environment do

  paths = ['public/javascripts/all.js', 'public/stylesheets/all.css', 'public/stylesheets/_cms.css']

  puts "-----> caching assets..."
  paths.each do |path|
    puts "-----> #{path}"
  end

  paths.each do |path|
    FileUtils.rm(path) if File.exist?(path)
  end

  ActionController::Base.perform_caching = true
  session = ActionDispatch::Integration::Session.new(Rails.application)
  session.get('/caching/cms_templates')
  session.get('/caching/app_templates')

  paths.each do |path|
    if File.exist?(path)
      system("git add #{path}") ? true : fail
    end
  end

  if paths.map {|path| %x[git status -s #{path}]}.any? {|p| p.present?}
    puts "-----> committing cached assets"
    system("git commit -m 'updating cache_assets'") ? true : fail
  else
    puts "-----> nothing to commit"
  end

  puts "-----> done"
end

deploy.rake

desc "cache assets, push to github, deploy to heroku, and notify hoptoad"
task :deploy => :environment do
  puts "-----> running rake cache_assets"
  system("rake cache_assets") ? true : fail

  puts "-----> pushing to github"
  system("git push origin master") ? true : fail

  puts "-----> deploying to heroku"
  system("git push heroku master") ? true : fail

  puts "-----> notifying hoptoad"
  system("rake hoptoad:deploy TO=production REVISION=`git rev-parse HEAD`") ? true : fail

  puts "-----> done"
end

work around devise auth by having a special route/controller setup for rendering particular layouts with no content

also checks that the expected files have been modified in git, not other unstaged changes, as the precondition for a new commit