Useful rails things

Group by week: As described here, in rails enumerable objects have a group_by method so you can do things like:

<% @posts.group_by(&:week).each do |week, posts| %>
  <div id="week">
    <h2>Week <%= week %></h2>
    <%= render :partial => 'post', :collection => @posts %>
  </div>
<% end %>