Merge pull request #263 from mstanleyjones/252_add_managed_plugin_toc

Add plugin dev doc to TOC

_data/toc.yaml

@@ -257,6 +257,8 @@ toc:
       title: Seccomp security profiles for Docker
   - sectiontitle: Extend Engine
     section:
+    - path: /engine/extend/
+    - title: Managed plugin system
     - path: /engine/extend/plugins_authorization/
       title: Access authorization plugin
     - path: /engine/extend/plugins/