text: (function(){
    var crypto = require('crypto');
  
    var gravatar = function(converter) {
      return [
        { type: 'lang', filter: function(source){
            return source.replace(/\[gravatar\]\((.*)\)/gi, function(match, email) {
              if (email) {
                var md5 = crypto.createHash('md5').update(email).digest("hex");
  
                return '<img src="http://www.gravatar.com/avatar/' + md5 + '?s=640" />';
              }
            });
        }}
      ];
    };
  
    if (typeof window !== 'undefined' && window.Showdown && window.Showdown.extensions) { window.Showdown.extensions.gravatar = gravatar; }
    if (typeof module !== 'undefined') module.exports = gravatar;
  }());
  