Added Docker Compose section

#18

@STaRDoGG please feel free to correct, or anything you'd like to improve on.

Author: JulianPrieber

README.md

@@ -153,6 +153,48 @@ docker run --detach \
 
 <br>
 
+#### Docker Compose
+
+<pre>
+version: "3.8"
+
+services:
+
+  littlelink-custom:
+    hostname: 'littlelink-custom'
+    image: 'julianprieber/littlelink-custom:latest'
+    environment:
+      TZ: 'Europe/Berlin'
+      SERVER_ADMIN: youremail@gmail.com'
+      HTTP_SERVER_NAME: 'yourdomain.com''
+      HTTPS_SERVER_NAME: 'yourdomain.com'
+      LOG_LEVEL: 'info'
+      PHP_MEMORY_LIMIT: '256M'
+      UPLOAD_MAX_FILESIZE: '8M'
+    volumes:
+      - '/opt/docker/configs/littlelink/config/.env:/htdocs/.env:rw'
+      - '/opt/docker/configs/littlelink/config/advanced-config.php:/htdocs/config/advanced-config.php:rw'
+      - '/opt/docker/configs/littlelink/config/img:/htdocs/img:rw'
+    ports:
+      - '8088:80'
+      - '8090:443'
+    networks:
+      - 'mariadb'
+      - 'misc'
+      - 'redis'
+networks:
+  misc:
+    external: true
+    name: 'misc'
+  mariadb:
+    external: true
+    name: 'db-mariadb'
+  redis:
+    external: true
+    name: 'db-redis'
+</pre>
+
+<br>
 
 #### You can now log in to the Admin Panel, on your defined ports, with the credentials:
 -   **email:** `admin@admin.com`