add new variables to sample

Author: LumePart

sample.env

@@ -49,11 +49,13 @@ LIBRARY_NAME=
 
 # YouTube Data API key (required if using youtube)
 YOUTUBE_API_KEY=
+# Custom file extension for tracks (e.g mp3) (default: opus)
+# TRACK_EXTENSION=opus
 # Custom path to ffmpeg binary (default: defined in $PATH)
 # FFMPEG_PATH=
 # Custom path to yt-dlp binary (default: defined in $PATH)
 # YTDLP_PATH=
-# Path to (optional) cookies file (default ./cookies.txt) (in docker this is set through volume mapping)
+# Path to (optional) cookies file (default: ./cookies.txt) (in docker this is set through volume mapping)
 # COOKIES_PATH=./cookies.txt
 # Comma-separated (without spaces) keywords to exclude from YouTube results (default: live,remix,instrumental,extended,clean,acapella)
 # FILTER_LIST=live,remix,instrumental,extended
@@ -90,6 +92,32 @@ YOUTUBE_API_KEY=
 # Set to true to merge featured artists into title (recommended), false appends them to artist field (default: true)
 # SINGLE_ARTIST=true
 
+# === Notifications ===
+
+## Discord
+
+# Application's (bot) token
+# DISCORD_BOT_TOKEN=
+# Channel ID where to send notifications (supports multiple IDs, use comma (without spaces) to separate them)
+# DISCORD_CHANNEL_ID=
+
+## HTTP
+
+# HTTP URL to send POST requests to (supports multiple URLs, use comma (without spaces) to separate them)
+# HTTP_RECEIVER=
+
+## Matrix
+
+# User ID for Matrix
+# MATRIX_USERID=
+# Room ID to send notifications in
+# MATRIX_ROOMID=
+# Homeserver URL that the room is created in
+# MATRIX_HOMESERVER_URL
+# Users Access token
+# MATRIX_ACCESSTOKEN
+
+
 # === Misc ===
 
 # Minutes to sleep between library scans (default: 2)