Rankings

This branch sets up and calculates a user's ranking and score.  In a sense this is the initial commit for the simulator portion of our world cup simulator.  Now on the dashboard once you join or create a group and refresh the page (I'll set it up to be dynamic later) all the required calculations will display below the groups list.  This change also slightly modifies the group_matches collection schema so be sure to remove your group_matches collection and run node scripts/setup.js again.

This branch should not be merged in until JOIN-GROUP is merged.