Allow admin to change mailchimp settings

[gscardine]

• [x] Create table "Settings" with mailchimp_api_key and mailchimp_active_members_list
• [x] Create MVC

For the View:

• [x] Instructions on how to get API key: http://kb.mailchimp.com/accounts/management/about-api-keys
• [x] Instructions on how to get list ID: http://kb.mailchimp.com/lists/managing-subscribers/find-your-list-id
• [ ] OR: 1) Get list of lists; 1a) If there is none, ask the user to give it a name and create one; 1b) Ask the user to choose one to be their "Active members list"; 2) Save it in the database
• needs API 3.0: https://github.com/pacely/mailchimp-api-v3
• POST /lists Create a new list: http://developer.mailchimp.com/documentation/mailchimp/reference/lists/
• [ ] When using mailchimp, get api_key/list_id from this database table

[bolom]

20 @gscardine

we will add the mailchimp settings in the field settings in Organisation

[gscardine]

Estimate: 4h