monkeypatching

  def svernut dimensions, resources
    gruppen = self.group_by{|e|[ dimensions.map{|dim| e.send(dim)} ]}
    output_array = []
    gruppen.each do |row|
      row_hash = Hash.new(0)

      dimensions.map{|dim| row_hash[dim] = row.second.first.send(dim)  }

      row.second.each do |elem|
        resources.each do |res|
          row_hash[res] += elem.send(res)
        end
      end
      output_array << row_hash
    end
    output_array
  end