Merge pull request #2536 from ottj3/patch-1

Mention DynamicEmbeddedDocument in usage docs.

docs/guide/defining-documents.rst

@@ -27,6 +27,8 @@ objects** as class attributes to the document class::
 As BSON (the binary format for storing data in mongodb) is order dependent,
 documents are serialized based on their field order.
 
+.. _dynamic-document-schemas:
+
 Dynamic document schemas
 ========================
 One of the benefits of MongoDB is dynamic schemas for a collection, whilst data
@@ -231,6 +233,9 @@ document class as the first argument::
     comment2 = Comment(content='Nice article!')
     page = Page(comments=[comment1, comment2])
 
+Embedded documents can also leverage the flexibility of :ref:`dynamic-document-schemas:`
+by inheriting :class:`~mongoengine.DynamicEmbeddedDocument`.
+
 Dictionary Fields
 -----------------
 Often, an embedded document may be used instead of a dictionary – generally