anchor.diff:  
   <br />
   
  -<%= link_to 'Add Irradiance', new_irradiance_path %>
  +<%= link_to 'Add irradiance', new_irradiance_path %>
  
positive.code:   <colgroup>
      <col />
      <col />
    </colgroup>
    <thead>
      <tr>
          <th>Direct</th>
          <th>Diffuse</th>
          <th>Postcode</th>
          <th></th>
        <th></th>
        <th></th>
      </tr>
  
negative.code:   <tbody>
    <% @irradiances.each do |irradiance| %>
      <tr>
        <td><%= irradiance.postcode.pcode %></td>
        <td><%= link_to 'Show', irradiance %></td>
        <td><%= link_to 'Edit', edit_irradiance_path(irradiance) %></td>
        <td><%= link_to 'Delete', irradiance, confirm: "Are you sure?", method: :delete %></td>
      </tr>
  