Basecamp probably belongs in Communication

After all, Trello and Yammer are in there too.
Add Mandrill email service
Verify the provided image actually exists

Will catch typo’s
Add Mixpanel
Update social.yml

Google is able to login with sms, app and *phone call* :-)
Update backup.yml
Update payments.yml
Merge pull request #425 from jonny0303/patch-2

Update backup.yml
Merge pull request #426 from jonny0303/patch-3

Update payments.yml
Merge pull request #424 from jonny0303/patch-1

Update social.yml
Merge pull request #423 from tijmenb/add-services

Add Mandrill, Mixpanel and add an image check