Add sms reminders.

Environment variables: encrypt for travis and add to config. Exclude
tests from running on travis.
Add task to fetch and send sms reminders
Add send sms reminders endpoint

Move test helper method for authentication somewhere reusable
Send tasks should inherit from base
Combine PostReminderSend tasks for each type
Combine module logic
Add rake task to test sending sms
Make send reminder base class abstract

Actually instantiate send reminder using child class
Ruby case