How can I configure my Sinatra application to use Cloudinary?

The cloudinary.yml file includes the settings for the different environments of Rails (development, production, test).
The recommended option is to define the 'CLOUDINARY_URL' environment variable. Alternatively, the configuration can be defined programatically in Sinatra initialization code as explained here:
http://cloudinary.com/documentation/rails_integration#configuration

For example:

Cloudinary.config do |config|
config.cloud_name = 'sample'
config.api_key = '874837483274837'
config.api_secret = 'a676b67565c6767a6767d6767f676fe1'
config.cdn_subdomain = true
end