anchor.diff:      [Subject Collection][]
   
   ### Create a Subject [POST]
  -A *locations* attributes and a project link are required.
  +A *locations* attribute and a project link are required.
   
   The *locations* array should have the mime-types of the subject's
  -associated media. The response will contain signed s3 urls the client
  -may make a PUT request containing the media to. The signed urls will
  -be valid for 20 minutes.
  -
  -The *metadata* attribute and a link to an owner besides
  -the active user are optional.
  +associated media. If a particular piece of media has multiple
  +representations (such as video encoded as WebM and MPEG-4) it's
  +mimetypes should be a subarray within the *locations* array, eg, for
  +subject whose media include an image and a video its *locations* array
  +would look like `"locations":["image/png", ["video/webm", "video/mp4"]]`.
  +
  +The response will contain signed s3 urls the client may make a PUT
  +request containing the media to. The signed urls will be valid for 20 minutes.
  +
  +The *metadata* attribute is optional.
   
   + Request
   
  
positive.code:                         "lens_type": "50mm"
                      },
                      "links": {
                          "project": "1",
                          "owner": {
                              "id": "2",
                              "href": "/users/2",
                              "type": "users"
                          }
                      }
                  }]
              }
  
negative.code: classifications from other members of a user_group, or projects the
  user has edit permissions for.
  
  Classifications have the special *for* parameter that indicates the
  scope of classifications you'd like to retrieve. Possible options are:
  
  + 'user' will fetch the current user's past classifications.
  + 'user_groups' will fetch classifications from groups a user is a member of
  + 'projects' will fetch classifications from projects a user has 'edit' permissions for
  
  Any of the for scopes may be further filtered using the *project_id*
  and *user_group_id* parameters. 
  
  + Parameters
      + page (optional, integer) ... index of the collection page, 1 is default
      + per_page (optional, integer) ... number of items on a page. 20 is default
      + sort (optional, string) ... fields to sort collection by. updated_at is default
      + project_id (optional, integer) ... only retrieve classifications for a specific project
      + user_group_id (optional, integer) ... only retrieve classifications for a specific user group
      + include (optional, string) ... comma seperated list of linked resources to return with the collection
      + for (optional, string) ... one of 'projects', 'user', 'user_groups', 'user' by default (see explanation above).
  
  + Request
  
  