Update plugins Readme (#680)

* Update plugins Readme

* Update README.md

* Minor formatting

Co-authored-by: Eyal <[email protected]>
Co-authored-by: Chris Mullins <[email protected]>

Author: 3 people

README.md

@@ -31,6 +31,9 @@ The following commands are currently available:
 * [Config](https://github.com/microsoft/botframework-cli/tree/master/packages/cli#bf-config)
 * [Luis][3]
 
+Preview commands (Install running [bf plugins](https://github.com/microsoft/botframework-cli/tree/master/packages/plugins#microsoftbf-cli-plugins))
+* [Dialog](https://github.com/microsoft/botframework-cli/tree/master/packages/dialog)
+
 #### Future Commands
 The following commands will be ported in upcoming releases:
 * Dispatch

packages/plugins/README.md

@@ -8,6 +8,19 @@ This package is intended for Microsoft use only and should be consumed through @
 [![Downloads/week](https://img.shields.io/npm/dw/@microsoft/bf-cli-plugins.svg)](https://npmjs.org/package/@microsoft/bf-cli-plugins)
 [![License](https://img.shields.io/npm/l/@microsoft/bf-cli-plugins.svg)](https://github.com/https://github.com/microsoft//botframework-cli/blob/master/package.json)
 
+## Synopsis
+_BF_ plugins command group allows you to extend the CLI with preview commands. Only microsoft scoped plugins are allowed to be installed.
+
+## Available plugins
+
+[@microsoft/bf-dialog](https://github.com/microsoft/botframework-cli/tree/master/packages/dialog)
+```
+npm config set registry https://botbuilder.myget.org/F/botframework-cli/npm/
+
+bf plugins:install @microsoft/bf-dialog
+
+npm config set registry https://registry.npmjs.org/
+```
 <!-- toc -->
 * [Commands](#commands)
 <!-- tocstop -->