support env for docker plugin set

Signed-off-by: Victor Vieux <vieux@docker.com>

docs/reference/commandline/plugin_disable.md

@@ -59,3 +59,4 @@ tiborvass/no-remove   latest              A test plugin for Docker   false
 * [plugin inspect](plugin_inspect.md)
 * [plugin install](plugin_install.md)
 * [plugin rm](plugin_rm.md)
+* [plugin set](plugin_set.md)

docs/reference/commandline/plugin_enable.md

@@ -59,3 +59,4 @@ tiborvass/no-remove   latest              A test plugin for Docker   true
 * [plugin inspect](plugin_inspect.md)
 * [plugin install](plugin_install.md)
 * [plugin rm](plugin_rm.md)
+* [plugin set](plugin_set.md)

docs/reference/commandline/plugin_inspect.md

@@ -159,3 +159,4 @@ $ docker plugin inspect -f '{{.Id}}' tiborvass/no-remove:latest
 * [plugin disable](plugin_disable.md)
 * [plugin install](plugin_install.md)
 * [plugin rm](plugin_rm.md)
+* [plugin set](plugin_set.md)

docs/reference/commandline/plugin_install.md

@@ -64,3 +64,4 @@ tiborvass/no-remove   latest              A test plugin for Docker   true
 * [plugin disable](plugin_disable.md)
 * [plugin inspect](plugin_inspect.md)
 * [plugin rm](plugin_rm.md)
+* [plugin set](plugin_set.md)

docs/reference/commandline/plugin_ls.md

@@ -48,3 +48,4 @@ tiborvass/no-remove   latest              A test plugin for Docker   true
 * [plugin inspect](plugin_inspect.md)
 * [plugin install](plugin_install.md)
 * [plugin rm](plugin_rm.md)
+* [plugin set](plugin_set.md)

docs/reference/commandline/plugin_rm.md

@@ -51,3 +51,4 @@ tiborvass/no-remove
 * [plugin disable](plugin_disable.md)
 * [plugin inspect](plugin_inspect.md)
 * [plugin install](plugin_install.md)
+* [plugin set](plugin_set.md)

docs/reference/commandline/plugin_set.md

@@ -0,0 +1,51 @@
+---
+title: "plugin set"
+description: "the plugin set command description and usage"
+keywords: "plugin, set"
+advisory: "experimental"
+---
+
+<!-- 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.
+-->
+
+# plugin set (experimental)
+
+```markdown
+Usage:  docker plugin set PLUGIN key1=value1 [key2=value2...]
+
+Change settings for a plugin
+
+Options:
+      --help                    Print usage
+```
+
+Change settings for a plugin. The plugin must be disabled.
+
+
+The following example installs change the env variable `DEBUG` of the
+`no-remove` plugin.
+
+```bash
+$ docker plugin inspect -f {{.Config.Env}} tiborvass/no-remove
+[DEBUG=0]
+
+$ docker plugin set DEBUG=1 tiborvass/no-remove
+
+$ docker plugin inspect -f {{.Config.Env}} tiborvass/no-remove
+[DEBUG=1]
+```
+
+## Related information
+
+* [plugin ls](plugin_ls.md)
+* [plugin enable](plugin_enable.md)
+* [plugin disable](plugin_disable.md)
+* [plugin inspect](plugin_inspect.md)
+* [plugin install](plugin_install.md)
+* [plugin rm](plugin_rm.md)