docs(site): added docker instructions to documentation site

docs/docker.md

@@ -1,3 +1,27 @@
 # Docker
 
-TODO
+Recommended and the easiest way how to start to use of Spooty is using docker.
+Just run docker command or use docker compose configuration. 
+
+### Docker command
+```shell
+docker run -d -p 3000:3000 -v /path/to/downloads:/spooty/backend/downloads raiper34/spooty:latest
+```
+
+### Docker compose
+```yaml
+services:
+  spooty:
+    image: raiper34/spooty:latest
+    container_name: spooty
+    restart: unless-stopped
+    ports:
+      - "3000:3000"
+    volumes:
+      - /path/to/downloads:/spooty/backend/downloads
+```
+
+### Environment variables
+Name | Description                                                                                                                                                      |
+--- |------------------------------------------------------------------------------------------------------------------------------------------------------------------|
+FORMAT | Format of downloaded files (currently fully supported only `mp3` but you can try whatever you want from [ffmpeg](https://ffmpeg.org/ffmpeg-formats.html#Muxers)) |

docs/index.html

@@ -25,5 +25,7 @@
 <script src="//cdn.jsdelivr.net/npm/docsify/lib/plugins/search.min.js"></script>
 <script src="//cdn.jsdelivr.net/npm/prismjs@1/components/prism-typescript.min.js"></script>
 <script src="//cdn.jsdelivr.net/npm/prismjs@1/components/prism-json.min.js"></script>
+<script src="//cdn.jsdelivr.net/npm/prismjs@1/components/prism-yaml.min.js"></script>
+<script src="//cdn.jsdelivr.net/npm/prismjs@1/components/prism-bash.min.js"></script>
 </body>
 </html>