Enhancement: add storage_path parameter to post_document API (#5217)

* Feature: add `storage_path` parameter to post_document API

* Complete coverage for validate_storage_path

---------

Co-authored-by: shamoon <4887959+shamoon@users.noreply.github.com>

src/documents/serialisers.py

@@ -966,6 +966,14 @@ class PostDocumentSerializer(serializers.Serializer):
         required=False,
     )
 
+    storage_path = serializers.PrimaryKeyRelatedField(
+        queryset=StoragePath.objects.all(),
+        label="Storage path",
+        allow_null=True,
+        write_only=True,
+        required=False,
+    )
+
     tags = serializers.PrimaryKeyRelatedField(
         many=True,
         queryset=Tag.objects.all(),
@@ -1005,6 +1013,12 @@ class PostDocumentSerializer(serializers.Serializer):
         else:
             return None
 
+    def validate_storage_path(self, storage_path):
+        if storage_path:
+            return storage_path.id
+        else:
+            return None
+
     def validate_tags(self, tags):
         if tags:
             return [tag.id for tag in tags]