title: Symfony2 Exception on web/web_dev.php
body: <p>Following the Symfony2 guide it says to view <code>web/web_dev.php</code> but I get a exception..
  The <code>app/check.php</code> is all fine except one optional test fails:</p>
  
  <pre><code>[[WARNING]] Checking that the intl ICU version is at least 4+: FAILED
              *** Upgrade your intl extension with a newer ICU version (4+) ***
  </code></pre>
  
  <p>This is the exception:</p>
  
  <pre><code>RuntimeException: Unable to create the cache directory (/var/www/projectname/www/Symfony/app/cache)
  in /var/www/projectname/www/Symfony/app/bootstrap.php.cache line 1197
  at Kernel-&gt;buildContainer() in /var/www/projectname/www/Symfony/app/bootstrap.php.cache line 1138
  at Kernel-&gt;initializeContainer() in /var/www/projectname/www/Symfony/app/bootstrap.php.cache line 869
  at Kernel-&gt;boot() in /var/www/projectname/www/Symfony/app/bootstrap.php.cache line 1038
  at Kernel-&gt;loadClassCache() in /var/www/projectname/www/Symfony/web/app_dev.php line 12
  </code></pre>
  
  <p>Thanks in advance for anyone who gives me light on how to solve this</p>