added after_create and after_destroy methods to team.rb that catches ranking errors when teams are created/destroyed on leaderboard page.
added after_create and after_destroy methods to team.rb that catches ranking errors when teams are created/destroyed on leaderboard page.

UM-USElab/gradecraft-development,UM-USElab/gradecraft-development,UM-USElab/gradecraft-development,UM-USElab/gradecraft-development