title: How to extend cache ttl (time-to-live) in django-redis?
body: <p>I'm using django 1.5.4 and django-redis 3.7.1</p>
  
  <p>I'd like to <b>extend cache's ttl(time-to-live)</b> when I retrieved it.</p>
  
  <p>Here is sample code</p>
  
  <pre><code>from django.core.cache import cache
  
  foo = cache.get("foo)
  
  if not foo:
      cache.set("foo", 1, timeout=100)
  else:
      // Extend Cache's Time-To-Live something like it
      cache.ttl("foo") = 200
  </code></pre>
  
  <p>I tried to search this option at <a href="http://niwibe.github.io/django-redis/#_why_use_django_redis" rel="noreferrer">django-redis-docs</a>, but I couldn't find it.</p>
  
  <p>However, I noticed that designate time-to-live value for existing cache is available at redis native command like "<code>Expire foo 100</code>"</p>
  
  <p>I know that using <code>cache.set</code> once more make same effect, but I'd like to use more simple method with time-to-live attribute.</p>