Added TOC to README.

Author: dblock

CHANGELOG.md

@@ -2,6 +2,7 @@
 
 * [#263](https://github.com/slack-ruby/slack-ruby-bot/pull/263): Removed Giphy support - [@dblock](https://github.com/dblock).
 * [#260](https://github.com/slack-ruby/slack-ruby-bot/pull/260): Add brief migration guide - [@wasabigeek](https://github.com/wasabigeek).
+* [#264](https://github.com/slack-ruby/slack-ruby-bot/pull/264): Added TOC to README - [@dblock](https://github.com/dblock).
 * Your contribution here.
 
 ### 0.15.0 (2020/5/8)

Dangerfile

@@ -1,3 +1,5 @@
 # frozen_string_literal: true
 
 danger.import_dangerfile(gem: 'slack-ruby-danger')
+
+toc.check!

Gemfile

@@ -14,5 +14,6 @@ if ENV.key?('CONCURRENCY')
 end
 
 group :test do
+  gem 'danger-toc', '~> 0.2.0', require: false
   gem 'slack-ruby-danger', '~> 0.1.0', require: false
 end

README.md

@@ -11,6 +11,52 @@ If you are not familiar with Slack bots or Slack API concepts, you might want to
 
 ![](slack.png)
 
+# Table of Contents
+
+- [Useful to Me?](#useful-to-me)
+- [Stable Release](#stable-release)
+- [Usage](#usage)
+  - [A Minimal Bot](#a-minimal-bot)
+    - [Gemfile](#gemfile)
+    - [pongbot.rb](#pongbotrb)
+  - [A Production Bot](#a-production-bot)
+  - [More Involved Examples](#more-involved-examples)
+  - [Commands and Operators](#commands-and-operators)
+  - [Threaded Messages](#threaded-messages)
+  - [Bot Aliases](#bot-aliases)
+  - [Generic Routing](#generic-routing)
+  - [Matching text in message attachments](#matching-text-in-message-attachments)
+  - [Providing description for your bot and commands](#providing-description-for-your-bot-and-commands)
+  - [Customize your command help output](#customize-your-command-help-output)
+  - [SlackRubyBot::Commands::Base](#slackrubybotcommandsbase)
+  - [Authorization](#authorization)
+  - [Built-In Commands](#built-in-commands)
+    - [[bot name]](#bot-name)
+    - [[bot name] hi](#bot-name-hi)
+    - [[bot name] help](#bot-name-help)
+  - [Hooks](#hooks)
+    - [Implementing and registering a Hook Handler](#implementing-and-registering-a-hook-handler)
+      - [Hooks registration on SlackRubyBot::Server initialization](#hooks-registration-on-slackrubybotserver-initialization)
+      - [Hooks registration on a SlackRubyBot::Server instance](#hooks-registration-on-a-slackrubybotserver-instance)
+      - [Hooks registration on SlackRubyBot::Server class](#hooks-registration-on-slackrubybotserver-class)
+    - [Deprecated hook registration](#deprecated-hook-registration)
+  - [Bot Message Protection](#bot-message-protection)
+  - [Message Loop Protection](#message-loop-protection)
+  - [Logging](#logging)
+  - [Advanced Integration](#advanced-integration)
+  - [Proxy Configuration](#proxy-configuration)
+  - [Model-View-Controller Design](#model-view-controller-design)
+    - [Controller](#controller)
+    - [Model](#model)
+    - [View](#view)
+  - [Testing](#testing)
+    - [RSpec Shared Behaviors](#rspec-shared-behaviors)
+    - [Testing Lower Level Messages](#testing-lower-level-messages)
+  - [Useful Libraries](#useful-libraries)
+- [Contributing](#contributing)
+- [Upgrading](#upgrading)
+- [Copyright and License](#copyright-and-license)
+
 ## Useful to Me?
 
 * If you are just trying to send messages to Slack, use [slack-ruby-client](https://github.com/slack-ruby/slack-ruby-client), which this library is built on top of.