anchor.diff:                  "subject_sets": [{
                       "id": "20",
                       "display_name": "Weird Looking Galaxies",
  +                    "metadata": {
  +                        "category": "things"
  +                    },
                       "created_at": "2014-02-13T10:11:34Z",
                       "updated_at": "2014-02-13T10:11:34Z",
                       "set_member_subject_cound": 100,
  
positive.code:                      },
                      "links": {
                          "project": "1",
                      }
                  }]
              }
  
negative.code:                      },
                      "links": {
                          "project": "1",
                          "subject_sets": ["10", "11", "12"]
                      }
                  }]
              }
  