fix: read vars from existing config file

setup

@@ -80,6 +80,14 @@ if [ $CONFIG_EXISTS == "false" ] || [ $USE_EXISTING_CONFIG == "n" ]; then
     echo "Config file 'config' created!"
 else
     echo "Use existing config file 'config'!"
+
+    while read line; do
+        if [[ $line == *"PAPERLESS_HOST_IP_ADDRESS="* ]]; then
+            PAPERLESS_HOST_IP_ADDRESS=$(echo $line | cut -c 27-)
+        elif [[ $line == *"PAPERLESS_HOST_PORT="* ]]; then
+            PAPERLESS_HOST_PORT=$(echo $line | cut -c 21-)
+        fi
+    done < "config"
 fi
 
 cat "config" >> ".env"