articles.rb

def send_email
  mg_client = Mailgun::Client.new("YOUR-API-KEY")

  message_params =  {
                     from: 'robin@percy.pw',
                     to:   IronWorker.payload['email'],
                     subject: 'Your daily developer articles!',
                     text: email_body()
                    }

  result = mg_client.send_message('YOUR-SANDBOX-URL.mailgun.org', message_params).to_h!

  message_id = result['id']
  message = result['message']
end