title: Inverted search from set with Redis
body: <p>I'm fairly new to Node.js and I'm trying to create a blog using Express and Redis.</p>
  
  <p>My problem is that I'm kind of lost in NoSQL and I can't really see how I should design my Redis data.</p>
  
  <p>I wanted to do :</p>
  
  <pre><code>SET global:postsNb 0
  SET posts:1:text blablabla
  SADD posts:1:tags a
  SADD posts:1:tags b
  SADD posts:1:tags c
  </code></pre>
  
  <p>It seems quite natural but I don't know how I can search <strong>all posts where a in tags</strong>.</p>
  
  <p>Could you help me pls ?</p>
  
  <p>Thanks in advance.</p>