gist_shortcode_wp.php

<?php

/* Adds a shortcode for displaying GitHub Gists */
function create_github_gist($atts) {
  extract(shortcode_atts(array(
    'source' => "https://gist.github.com/SufferMyJoy/9397075",
  ), $atts));
  return '<script src="' . esc_attr( $source ) . '.js"></script>';
}

add_shortcode('github_gist', 'create_github_gist');

?>