add last_adopted_at to user model to track when user last adopted a thing
update user.last_adopted_at in DB when they adopt a thing
change honolulu.gov email sender addresses to oaklandnet.com addresses
add httparty to simplify sending requests to GovDelivery
update domain for mailer to adoptadrainoakland.com
Added rake task subscribe_recent_adopters.

This task should be run periodically to subscribe recent adopters to an email list managed
by GovDelivery. It subscribes all users for whom the new subscribed_at column is null.
The column is updated after they are subscribed. To resubscribe a user, that column must be
set back to null.
Merge pull request #14 from RobertStewart/subscribe_adopters

Subscribe adopters