Added children_ids to the entity attributes serialized in to_json.

platypush/entities/_base.py

@@ -196,11 +196,14 @@ if 'entity' not in Base.metadata:
             """
             Returns the current entity as a flatten dictionary.
             """
-            return dict(
+            return {
+                **dict(
                     self._column_to_pair(col)
                     for col in self.columns
                     if self._column_to_pair(col)
-            )
+                ),
+                'children_ids': [c.id for c in self.children],
+            }
 
         def to_json(self) -> dict:
             """