Move stops to top level of trips and status_changes object

provider/README.md

@@ -253,7 +253,9 @@ Schema: [`trips` schema][trips-schema]
 | `route` | GeoJSON `FeatureCollection` | Required | See [Routes](#routes) detail below |
 | `accuracy` | Integer | Required | The approximate level of accuracy, in meters, of `Points` within `route` |
 | `start_time` | [timestamp][ts] | Required | |
+| `start_stop_id` | UUID | Required (*docked*), Optional (*dockless*) | Identifier for a stop see [Stops](LINKTBD). |
 | `end_time` | [timestamp][ts] | Required | |
+| `end_stop_id` | UUID | Required (*docked*), Optional (*dockless*) | Identifier for a stop see [Stops](LINKTBD). |
 | `publication_time` | [timestamp][ts] | Optional | Date/time that trip became available through the trips endpoint |
 | `parking_verification_url` | String | Optional | A URL to a photo (or other evidence) of proper vehicle parking |
 | `standard_cost` | Integer | Optional | The cost, in the currency defined in `currency`, that it would cost to perform that trip in the standard operation of the System (see [Costs & Currencies](#costs--currencies)) |
@@ -344,7 +346,8 @@ Schema: [`status_changes` schema][sc-schema]
 | `event_location` | GeoJSON [Point Feature][geo] | Required | |
 | `battery_pct` | Float | Required if Applicable | Percent battery charge of device, expressed between 0 and 1 |
 | `associated_trip` | UUID | Required if Applicable | Trip UUID (foreign key to Trips API), required if `event_type_reason` is `user_pick_up` or `user_drop_off`, or for any other status change event that marks the end of a trip. |
-| `associated_ticket` | String | Optional | Identifier for an associated ticket inside an Agency-maintained 311 or CRM system. | 
+| `associated_ticket` | String | Optional | Identifier for an associated ticket inside an Agency-maintained 311 or CRM system. |
+| `stop_id` | UUID | Conditionally Required (*docked*), N/A (*dockless*) | Identifier for a stop see [Stops](LINKTBD). Required for `trip_start` and `trip_end` events for a *docked* mobility provider. |
 
 ### Event Times