Add YouTube audio playback capabilities

Added YouTube audio playback capabilities for listening to music in voice channels.

Author: Gisgar3

commands.json

@@ -5,14 +5,18 @@
         "/ratz slimedog",
         "/ratz discorduserinfo + UserID",
         "/ratz botinfo",
-        "/ratz releaseinfo"
+        "/ratz releaseinfo",
+        "/ratz play + YouTube URL",
+        "/ratz stop"
     ],
     "definitions": [
         "Shows all commands for ratzBot",
         "Shows user information for provided Steam64 ID",
         "Authorizes user to type in server chat after reading the rules",
         "Shows user information for provided numerical Discord ID (not discriminator)",
         "Shows all information about ratzBot",
-        "Shows the latest release information of ratzBot"
+        "Shows the latest release information of ratzBot",
+        "Plays YouTube video audio",
+        "Stops YouTube video audio"
     ]
 }

main.js

@@ -1,5 +1,10 @@
+// COPYRIGHT (C) GAVIN ISGAR 2017-2018
+
 const Discord = require("discord.js");
 const DiscordRPC = require("discord-rpc");
+const opus = require("opusscript");
+const ffmpeg = require("ffmpeg-binaries");
+const ytdl = require("ytdl-core");
 const bot = new Discord.Client();
 const msg = new Discord.Message();
 var net = require('net');
@@ -167,6 +172,43 @@ bot.on('message', (message) => {
                         }
                     })
                 }
+                // -----VOICE CHANNELS-----
+                if (message.content.startsWith("/ratz play ")) {
+                    var result = message.content.slice(11);
+                    if (message.member.voiceChannel) {
+                        message.member.voiceChannel.join().then(connection => {
+                            try {
+                                const stream = ytdl(result, { filter: `audioonly` });
+                                const dispatcher = connection.playStream(stream);
+                                message.channel.send(`${message.author}, your music is now playing.`);
+                                dispatcher.on("end", end => {
+                                    message.channel.send(`${message.author}, your music has ended.`);
+                                    message.member.voiceChannel.leave();
+                                })
+                            }
+                            catch (err) {
+                                message.channel.send(`${message.author}, an error occured during the process. Try again later.`);
+                            }
+                        })
+                    }
+                    else {
+                        message.channel.send(`${message.author}, you are not in a voice channel. Join a voice channel to play music!`);
+                    }
+                }
+                if (message.content.toString() == "/ratz stop") {
+                    if (message.member.voiceChannel) {
+                        try {
+                            message.member.voiceChannel.connection.disconnect()
+                            message.member.voiceChannel.leave();
+                        }
+                        catch (err) {
+                            message.channel.send(`${message.author}, an error occured during the process. Try again later.`);
+                        }
+                    }
+                    else {
+                        message.channel.send(`${message.author}, you are not in a voice channel.`);
+                    }
+                }
                 // -----TOPIC DETECTION AND REVIEW-----
                 if ((message.content.includes("XXXTentacion") || message.content.includes("xxxtentacion")) && (message.content.includes("death") || message.content.includes("died"))) {
                     if (fs.readFileSync("./exclude/approvedmessages.ratz").includes(message.content.toString())) {