this is a format for datetimes NOT dates! the name should change. and it should not be in this file.
`DATE_FORMAT` is a default django setting (https://docs.djangoproject.com/en/1.3/ref/settings/#date-format), so moving it into the settings file may inadvertently change date formats elsewhere in the application. if it must be a custom setting, then give it a very explicit name, such as `UREPORT_JSON_API_DATETIME_FORMAT`

another option is to explicitly override the default `DATETIME_FORMAT` setting (https://docs.djangoproject.com/en/1.3/ref/settings/#datetime-format), but again this may have unintended effects on other datetimes that are displayed elsewhere by ureport.
also note that `DATE_FORMAT` and `DATETIME_FORMAT` django settings are only honored if `USE_L10N=True`

an alternative would be to define a custom `JSONEncoder` subclass and pass that to `json.dumps` in `create_json_response`
this is probably the best choice, so if any future API methods return dates, the formatting is performed in only one place and is consistent across all API calls