title: How to add a simple drop down in rails for pages
body: <p>I used will_paginate to paginate, now I want to control how many records in one page.
  I do know how to interact data from the select_tag. please tell me how to return the data to 
  @page in controller.</p>
  
  <p>I used </p>
  
  <pre><code>&lt;td&gt;&lt;%= select_tag "count", "&lt;option&gt;10&lt;/option&gt; &lt;option&gt;20&lt;/option&gt;".html_safe%&gt;&lt;/td&gt;
  </code></pre>
  
  <p>Controller</p>
  
  <pre><code>def index
    @page = 10;
    @users = User.order(:username).joins(:biography).where("`is_active?` = true AND `last_sign_in_at` &gt; DATE_SUB(NOW(), INTERVAL 6 MONTH) ").paginate(:page =&gt; params[:page], :per_page =&gt; @page)
  end
  </code></pre>