app/views/plates/show.csv.erb
<%= CSV.generate_line ["Sample", "Source Well", "Destination Well", "Source Volume" ], row_sep: "" %>
<% @presenter.transfers.each_with_index do |transfer, index| -%>
<% source_well, destination_well = transfer -%>
<%= CSV.generate_line [(index + 1), source_well, destination_well, nil], row_sep: "" %>
<% end -%>