Added id to article edit payload and 404 response

api.yaml

@@ -183,6 +183,11 @@ paths:
         content:
           application/json:
             schema:
+              type: object
+              properties:
+                id:
+                  type: number
+                  description: Id of the article to edit
               $ref: '#/components/schemas/Article'
       security:
         - cookie: []
@@ -195,6 +200,8 @@ paths:
                 $ref: '#/components/schemas/ArticleSummary'
         401:
           description: Not authorized
+        404:
+          description: Article was not found
         409:
           description: A article with the same title already exists