title: Redis add element value to a set in a transaction
body: <p>I'm very new to redis and I'm trying to do the following inside a tranaction:</p>
  
  <p>increment key
  add incremented value from before to a set</p>
  
  <p>using redis commands it would be something like</p>
  
  <pre><code>multi
  i = incr "value"
  sadd "set" i
  exec
  </code></pre>
  
  <p>Is there any redis command that would do that in one step with out needing two transactions and handling the value from the code (python code in my case)?</p>
  
  <p>Many thanks</p>