Fix some redirect loops and problems

Signed-off-by: Misty Stanley-Jones <misty@docker.com>

docs/extend/config.md

@@ -1,7 +1,4 @@
 ---
-aliases: [
-"/engine/extend/"
-]
 title: "Plugin config"
 description: "How develop and use a plugin with the managed plugin system"
 keywords: "API, Usage, plugins, documentation, developer"

docs/extend/index.md

@@ -1,6 +1,4 @@
 ---
-aliases:
-- /engine/extend/
 description: Develop and use a plugin with the managed plugin system
 keywords: "API, Usage, plugins, documentation, developer"
 title: Managed plugin system

docs/extend/legacy_plugins.md

@@ -1,5 +1,6 @@
 ---
-aliases: "/engine/extend/plugins/"
+redirect_from:
+- "/engine/extend/plugins/"
 title: "Use Docker Engine plugins"
 description: "How to add additional functionality to Docker with plugins extensions"
 keywords: "Examples, Usage, plugins, docker, documentation, user guide"

docs/extend/menu.md

@@ -1,18 +0,0 @@
----
-title: "Implement plugins"
-description: "Develop plugins and use existing plugins for Docker Engine"
-keywords: ["extend, plugins, docker, documentation, developer"]
-type: "menu"
-identifier: "engine_extend"
----
-
-<!-- This file is maintained within the docker/docker Github
-     repository at https://github.com/docker/docker/. Make all
-     pull requests against that repo. If you see this file in
-     another repository, consider it read-only there, as it will
-     periodically be overwritten by the definitive file. Pull
-     requests which include edits to this file in other repositories
-     will be rejected.
--->
-
-<!--menu page not rendered-->

docs/extend/plugins_authorization.md

@@ -2,7 +2,8 @@
 title: "Access authorization plugin"
 description: "How to create authorization plugins to manage access control to your Docker daemon."
 keywords: "security, authorization, authentication, docker, documentation, plugin, extend"
-aliases: ["/engine/extend/authorization/"]
+redirect_from:
+- "/engine/extend/authorization/"
 ---
 
 <!-- This file is maintained within the docker/docker Github