Add Help command

src/Commands/HelpCommand.php

@@ -0,0 +1,34 @@
+<?php
+
+namespace Longman\TelegramBot\Commands\UserCommands;
+
+use Longman\TelegramBot\Commands\UserCommand;
+use Longman\TelegramBot\Entities\ServerResponse;
+
+class HelpCommand extends UserCommand
+{
+    /** @var string */
+    protected $name = 'help';
+
+    /** @var string */
+    protected $description = 'Show bot commands help';
+
+    /** @var string */
+    protected $usage = '/help';
+
+    /** @var string */
+    protected $version = '1.0.0';
+
+    public function execute(): ServerResponse
+    {
+        return $this->replyToChat(
+            <<<END
+            This bots detects a Twitter link and reply with a [FixTweet](https://github.com/FixTweet/FixTweet) replacement.
+
+            _If added to a group chat, the bot has to be able to read all the messages._
+            END, [
+                'parse_mode' => 'markdown',
+                'disable_web_page_preview' => true,
+            ]);
+    }
+}