scope.rb

  scope :for_project_and_date_range, lambda { |project, lower, upper|
    if lower.cweek < upper.cweek 
      where(project_id: project.id, year: lower.year, cweek: Range.new(lower.cweek,upper.cweek)) 
    else # The date range spans over two years 
      query = "project_id = ? AND ((cweek > ? AND year = ?) OR (cweek < ? AND year = ?))"
      where(query, project.id, lower.cweek, lower.year, upper.cweek, upper.year)
    end
  }