Updgrade to createsend 3.1.1 which includes fix for refreshing OAuth access tokens.
Use the Heroku API to set the CAMPAIGN_MONITOR_ACCESS_TOKEN environment variable when a Campaign Monitor OAuth access token has been refreshed.
Use .env rather than config.yaml for local development. This removes messy config setup code which was previously in the configure block.
Fixed bug in usage of heroku-api gem.
Merge pull request #2 from skateistan/use-heroku-api-to-persist-env-vars-when-required

Use Heroku API to persist refresh CM OAuth access token + Don't use YAML to load config locally