update asset history docs

Author: Daria Mitrofanova

docs/backend-api/resources/commons/history/history_asset.md

@@ -82,10 +82,12 @@ Interval will be restricted by store period interval.
              "emergency": false,
              "employee_id": 4563
          },
-         "asset": {
-             "id": 1683258,
-             "type": "employee"
-         }
+         "assets": [
+             {
+                 "id": 1683258,
+                 "type": "employee"
+             }
+         ]
     }],
     "limit_exceeded": false,
     "total": 150,
@@ -94,7 +96,7 @@ Interval will be restricted by store period interval.
 }
 ```
 
-* `list` - list of zero or more history_entry` objects which described in [Tracker history entry](./index.md#tracker-history-entry) with additional optional asset parameter. 
+* `list` - list of zero or more history_entry` objects which described in [Tracker history entry](./index.md#tracker-history-entry). 
 * `limit_exceeded` - boolean. `false` when listed all history entries satisfied with conditions and `true` otherwise.
 * `total` - int. Amount of history entries satisfied with conditions.
 * `total_unread` - int. Amount of unread history entries satisfied with conditions.

docs/backend-api/resources/commons/history/index.md

@@ -40,7 +40,17 @@ Find instructions on getting notifications [here](../../../guides/rules-notifica
         "tracker_label": "Tracker label",
         "emergency": false,
         "employee_id": 4563
-    }
+    },
+    "assets": [
+        {
+            "id": 4563,
+            "type": "employee"
+        },
+        {
+            "id": 6345,
+            "type": "vehicle"
+        }
+    ]
 }
 ```
 
@@ -72,6 +82,9 @@ Find instructions on getting notifications [here](../../../guides/rules-notifica
     * `sensor_id` - optional int. Related sensor ID.
     * `sensor_name` - optional string. Related sensor name.
     * `sensor_calculated_value` - optional string. Related sensor value.
+* `assets` - optional array of objects. List of related objects containing identifier and type.
+    * `id` - int. Identifier of the asset.
+    * `type` - string. Type of the asset. Can be "vehicle" or "employee".
 
 Date/time type described in [data types description section](../../../getting-started/introduction.md#data-types).