add notification model
index for notifications
add access controll for notifications
Improve notification views
Add read and timestamps to notification
Add levels to notification and refactor view
create notifications on station up / down
Refactor station status checks
Removes duplication when checking status via rake #29, #48
Merge 'master' into 'notifications'
This rebases notifications onto the master branch in anticipation for a merge
Fix case where station with less than three measures is down.
paginate measures
seed random notifications
Merge pull request #50 from remote-wind/notifications

Closes #48