new Conflict(modelId, SourceModel, TargetModel)
    When two changes conflict a conflict is created.
**Note**: call `conflict.fetch()` to get the `target` and `source` models.
    Parameters:
| Name | Type | Description | 
|---|---|---|
| modelId | * | |
| SourceModel | PersistedModel | |
| TargetModel | PersistedModel | 
Properties:
| Name | Type | Description | 
|---|---|---|
| source | ModelClass | The source model instance | 
| target | ModelClass | The target model instance | 
- Source: