title: Rails : form select helper to have a starting default
body: <p>I have a simple form.
  Also as part of the form I have a variable with an array/list of all the country names.
  The form picks up the list just fine, however, it starts off on the first value, I think its <code>Afghanistan</code>, however I want it to start/default with <code>United Kingdom</code></p>
  
  <p>This is my code for the form select for the countries.</p>
  
  <pre><code>&lt;%= f.select(:country, @country_list.map { |value| [ value, value ] }) %&gt;
  </code></pre>
  
  <p>I have tried without success:</p>
  
  <pre><code>&lt;%= f.select(:country, @country_list.map { |value| [ value, value ] },['United Kingdom']) %&gt;
  </code></pre>