Method to add a member to the list.
https://api.wbsrvc.com/List/SubscribeEmail/
POST
| user_key Required |
User Key of the user who initiates the call. Type: string |
| list_id Required |
ID of the list. Type: integer |
| autoresponders Optional |
Trigger the autoresponders. Type: string - possible value 'true', 'false' |
| triggers Optional |
Trigger the welcome email. Type: string - possible value 'true', 'false' |
| email Required |
Email address of the member. Type: string |
| data Optional |
Additional data for the member. Type: array of fields and values - i.e. array('firstname' => 'John') |
| client_id Optional |
Client ID of the client in which the list is located. Type: integer |