title: checkbox to update attribute
body: <p>[Updated a bit] I have a Task model that has a :completed boolean attribute. If I click on it I want it to execute the 'finish' method. The main problem is that I am displays a series of checkboxes in a list and subsequent checkboxes after the first one are ignored. The method is never called for the given task/checkbox combo.</p>
  
  <p>I have this chunk of code in my view:</p>
  
  <pre><code>&lt;% current_user.tasks.each do |t|%&gt;
        &lt;% if t.completed == false %&gt;
            &lt;%= check_box_tag :completed, true, checked = false   %&gt;
            &lt;%= observe_field :completed, :url =&gt; { :controller =&gt; 'tasks', :action =&gt; :finish , :id =&gt; t.id },
                :frequency =&gt; 0.25,
                :update =&gt; :completed,
                :with =&gt; true
            %&gt;
  </code></pre>
  
  <p>and my finish method looks like this:</p>
  
  <pre><code>def finish
        @task = Task.find(params[:id])
        new = {:completed =&gt; true}
        @task.update_attributes(new)
        render :update do |page|
        page.replace_html "taskListing", :partial =&gt; 'home/task_listing'
   end
  </code></pre>