initial_data.json

[{
    "pk": 1,
    "model": "auth.user",
    "fields": {
        "username": "admin",
        "first_name": "",
        "last_name": "",
        "is_active": true,
        "is_superuser": true,
        "is_staff": true,
        "last_login": "2013-10-04T23:58:16Z",
        "groups": [],
        "user_permissions": [],
        "password": "pbkdf2_sha256$10000$TinFrvc34uKO$pOCziU7HO9ttS/0pkvp9SyfBiDcWQUc5fdk5GKTJpGc=",
        "email": "root@example.com",
        "date_joined": "2013-10-04T23:58:16Z"
    }
}]

The model changed to "model": "sentry.user"