title: htaccess regex, allow underscores
body: <p>Here is our current regex:</p>
  
  <pre><code>RewriteRule ^share/([a-zA-Z0-9-]+)/([a-zA-Z0-9-]+)/?$ /v.php?v=$1&amp;hash=$2 [L]
  </code></pre>
  
  <p>This isn't allowing underscores "_" - how do we get this to allow underscores?</p>
  
  <p>Thank you</p>