Tests for incrementing/resetting sit streaks.
Add streak attribute to User.
Basic working implementation; tests passing but more needed.
Test: don't increment twice in a day.
Misc: add scopes, default streak to 0, remove streak from attr_accessible.
Rake task to reset user.streak if they've missed a day.
Expose streak on sit view.
Update streak box styling, move up to user summary.
Show sit streaks - how many days someone has sat in a row. Fixes #95
Users followers/following pages accessible to all.