title: RestKit ios - put - json instead of form encoded
body: <p>i am writing an ios app that uses restkit to communicate with a web server through Rest with JSON</p>
  
  <p>i am able to use [[RKObjectManager sharedManager] loadObjectsAtResourcePath:path delegate:self] to get object from my web service as JSON, map it to obj-c object, it works fine</p>
  
  <p>now i am trying to use: [[RKObjectManager sharedManager] putObject:obj delegate:self]; and this call sends an object to the web service as form encoded and not JSON</p>
  
  <p>so my question is: how to configure the sharedManager (or the routeur?) to send with content type JSON instead of form encoded.</p>
  
  <p>any code example much appreciated.</p>
  
  <p>Thx!</p>