Mailchimp and COD integration

[timwood]

From @jdearie on July 27, 2015 14:31

We need to look into connecting the ticket registrations with our mailchimp lists. Right now, the two are completely separate and have to be managed manually. As new tickets were issued, those users weren't added to our mailchimp list unless I manually added or imported them.

We should look into https://www.drupal.org/project/mailchimp

Copied from original issue: Drupal4Gov/Drupal-GovCon-2015#147