What ikegami said, plus make sure to read your original code–

[% FOR tech IN users.all -%]
       <tr>
               <td>[% users.id %]</td>
[download]

The problem is you called each object in the resultset tech but tried to access it as users. This would be fine too–

[% FOR tech IN users.all -%]
       <tr>
               <td>[% tech.id %]</td>
[download]

I was joking above about keeping it consistent (always calling them user) because it has led to confusion a couple of times, not that tech is somehow wrong.