anchor.diff:  [source,json,linenums]
   ----
   {
  -  "groupId" : "sales",
  +  "group" : "sales",
     "type" : "candidate",
   }
   ----
  
positive.code: ----
  [
    {
      "userId" : "kermit",
      "groupId" : null,
      "type" : "candidate",
      "url" : "http://localhost:8081/activiti-rest/service/runtime/tasks/100/identitylinks/users/kermit/candidate"
    },
    {
      "userId" : null,
      "groupId" : "sales",
      "type" : "candidate",
      "url" : "http://localhost:8081/activiti-rest/service/runtime/tasks/100/identitylinks/groups/sales/candidate"
    },
  
negative.code: ----
  
  
  Note that the +group+ will always be null, as it's only possible to involve users with a process-instance.
  
  
  ==== Add an involved user to a process instance
  