course medium

docs/1.0.md

@@ -905,6 +905,8 @@ The node value is a string denoting one of the following possible values:
 - `publisher` - Describes a feed that links to other feeds a publisher owns using the `<podcast:remoteItem>` element.
   To understand the structure of how "publisher" feeds work, please see the dedicated document 
   [here](/publishers/publishers.md) and the `<podcast:publisher>` tag [here](#publisher).
+- `course` - A feed of training material (audio or video courses) with each item being a session or chapter of the 
+  course or conference track.
 
 ### List Mediums
 In addition to the above mediums, each medium also has a counterpart "list" variant, where the original medium name