Cross Origin Request Headers for Sinatra

environment.rb

# Add the following before filter at the end of the following
# block, found in your backend's config/environment.rb
#
# configure do
#   ...
#   ...
#   [insert before filter here]
# end

before do
  headers 'Access-Control-Allow-Origin' => '*', 
          'Access-Control-Allow-Methods' => ['OPTIONS', 'GET', 'POST']  
end

The gist has been updated, removing PUT and DELETE methods. Since those depend on preflight OPTIONS request. I'm looking into this gem (https://github.com/britg/sinatra-cross_origin) for Sinatra to see about enable to the full spectrum of HTTP requests with CORS.