Update shoulda-matchers
Remove competition start date validation

This is really getting in the way of creating data for tests, and it
doesn't currently server any purpose, since there's no functionality to
create a competition via the app.
Track intermediate scores on memberships

Adds a ride_count column to the memberships table, which keeps track of
a user's contribution to a team. Changes the score calculation process
to utilize the intermediate values.
Add script to update ride counts
Merge branch 'score-performance'