feat: add chat user model

Author: wxg0103

apps/users/api/user.py

@@ -152,6 +152,11 @@ def get_parameters():
             required=False,
         )]
 
+    @staticmethod
+    def get_request():
+        return serializers.ListSerializer(child=serializers.CharField(required=True), required=True,
+                                          label=_('User IDs'))
+
     @staticmethod
     def get_response():
         return UserListResponse