Well, to get Bootstrap working, first install Less Rails Bootstrap.
Then create a button with a fancy icon like so:
<%= link_to raw('<i class="icon-trash icon-white"></i>'), card, confirm: 'Are you sure?', method: :delete, :class => 'btn btn-danger' %>
Note that you have to link to raw
to get it to not escape the HTML.
Then you'll get something like this:
Thanks Andynu.