Update team's scores when challenges points has been changed

[Abdulwahaab710]

When a user updates the points for a challenge, we should update the score for all team in a background job. Maybe something like the following:

Team.all.each do |team|
  team.update(score: calculate_team_new_score(team))
end

def calculate_team_new_score(team)
  Submission.where(team: team, valid_submission: true).map { |s| s.challenge.points }.sum
end