Added _id return from save_file and kwargs to be stored in the document

Author: achawkins

flask_pymongo/__init__.py

@@ -214,7 +214,7 @@ def get_upload(filename):
         response.make_conditional(request)
         return response
 
-    def save_file(self, filename, fileobj, base="fs", content_type=None):
+    def save_file(self, filename, fileobj, base="fs", content_type=None, **kwargs):
         """Save a file-like object to GridFS using the given filename.
 
         .. code-block:: python
@@ -240,4 +240,4 @@ def save_upload(filename):
             content_type, _ = guess_type(filename)
 
         storage = GridFS(self.db, base)
-        storage.put(fileobj, filename=filename, content_type=content_type)
+        return storage.put(fileobj, filename=filename, content_type=content_type, **kwargs)