text: document.addEventListener('DOMContentLoaded', function() {
    var weekAgo = new Date().setDate(new Date().getDate() - 7)
    chrome.history.search({text: 'stackoverflow.com', startTime: weekAgo, endTime: Date.now()}, function(data) {
      var rating = data.reduce(function(previousValue, currentValue){
        return previousValue + currentValue.visitCount
      }, 0)
      document.getElementById('so-rating').innerText = rating
    });
  });
  