Changes to ERD:
1) Made copilot_profile#show_copilot_earnings NOT NULL.
2) Added auditing fields to copilot_profile_status.
3) Removed field copilot_project_plan#planned_contests.
4) Made planned_contest#project_category_id NOT NULL.
5) Renamed copilot_project_plan#planned_bugraces to planned_bug_races.
6) Renamed status_copilot_profile_status_id in copilt_profile table to copilot_profile_status_id.