Document SSH commands gerrit plugin {ls|install|remove|reload}

Change-Id: If6a45760cbc4ebdfb6cfeea4b39034cae1415b82
Signed-off-by: Edwin Kempin <edwin.kempin@sap.com>

Documentation/cmd-plugin-install.txt

@@ -0,0 +1,71 @@
+plugin install
+==============
+
+NAME
+----
+plugin install - Install/Add a plugin.
+
+plugin add - Install/Add a plugin.
+
+SYNOPSIS
+--------
+[verse]
+'ssh' -p <port> <host> 'gerrit plugin install | add'
+  [--name <NAME> | -n <NAME>]
+  - | <URL> | <PATH>
+
+DESCRIPTION
+-----------
+Install/Add a plugin. The plugin will be copied into the site path's
+`plugins` directory.
+
+ACCESS
+------
+Caller must be a member of the privileged 'Administrators' group.
+
+SCRIPTING
+---------
+This command is intended to be used in scripts.
+
+OPTIONS
+-------
+-::
+	Plugin jar as piped input.
+
+<URL>::
+	URL from where the plugin should be downloaded. This can be an
+	HTTP or FTP site.
+
+<PATH>::
+	Absolute file path to the plugin jar.
+
+--name::
+-n::
+	The name under which the plugin should be installed.
+
+EXAMPLES
+--------
+Install a plugin from an absolute file path on the server's host:
+
+====
+	ssh -p 29418 localhost gerrit plugin install -n name \
+	  $(pwd)/my-plugin.jar
+====
+
+Install a plugin from an HTTP site:
+
+====
+	ssh -p 29418 localhost gerrit plugin install -n name \
+	  http://build-server/output/our-plugin.jar
+====
+
+Install a plugin from piped input:
+
+====
+	ssh -p 29418 localhost gerrit plugin install -n name \
+	  - <target/name-0.1.jar
+====
+
+GERRIT
+------
+Part of link:index.html[Gerrit Code Review]