add shipments

lib/pages/staff/model/staff_model.dart

@@ -85,4 +85,29 @@ class StaffModel extends BaseModel {
   Future<User> findUser(String phoneNumber) {
     return Services.instance.userService.findUser(phoneNumber);
   }
+
+  Future<List<User>> getPickupEmployees() async {
+    if (user == null || !user.hasShipment()) return [];
+    return _getUsers(privilege_shipment);
+  }
+
+  Future<List<User>> _getUsers(String privilege) async {
+    List<User> users = [];
+    try {
+      var snaps = await Firestore.instance
+          .collection("/$user_collection")
+          .where("is_employee", isEqualTo: true)
+          .where("is_sys_admin", isEqualTo: false)
+          .where("privileges", arrayContains: privilege)
+          .getDocuments(source: Source.server);
+      users = snaps.documents.map((documentSnapshot) {
+        var user =
+            User.fromMap(documentSnapshot.data, documentSnapshot.documentID);
+        return user;
+      }).toList();
+    } catch (e) {
+      log.warning("Error!! $e");
+    }
+    return users;
+  }
 }