rack_canonical = <<CANONICAL

#Run heroku config:add CANONICAL_HOST=yourdomain.com
#For more information, see: https://github.com/tylerhunt/rack-canonical-host#usage
use Rack::CanonicalHost, ENV['CANONICAL_HOST'] if ENV['CANONICAL_HOST']
CANONICAL

inject_into_file 'config.ru', rack_canonical, {after: "require ::File.expand_path('../config/environment',  __FILE__)", verbose: false}

git add: 'config.ru'
git_commit 'Add rack-canonical-host.'