title: incrementing a score in redis sorted sets
body: <p>I want to track daily usage statistics using redis's sorted sets in which the score would be the time stamp and the member would be the value of that specific statistic (since I want to use zrange to fetch the statistics)</p>
  
  <p>so if I have a visits key</p>
  
  <p><code>zadd "visits", "20131211", 1</code> # which would add a single visit to the date of today dec 11, 2013</p>
  
  <p>but what happens in the other visits?</p>
  
  <p>How do I increment the score of a member? </p>
  
  <p>I feel may be confusing the purpose of <code>member</code> and <code>score</code></p>