gistfile1.rb

#before
def load_submissions_count
    Enrollment.where(initiative_id: @initiative_ids).group(:initiative_id).select('initiative_id, sum(submissions_count) as sum_submissions_count').each do |data|
      initiative = @initiatives_data[data.initiative_id]
      initiative.cached_submissions_count = data.sum_submissions_count.to_i
    end
  end

#after
def load_submissions_count
    Enrollment.where(initiative_id: @initiative_ids).group(:initiative_id).select('initiative_id, COALESCE(sum(submissions_count), 0) as sum_submissions_count').each do |data|
      initiative = @initiatives_data[data.initiative_id]
      initiative.cached_submissions_count = data.sum_submissions_count.to_i
    end
  end