Improve README about docker command

README.md

@@ -61,9 +61,9 @@ docker build -t iotaledger/goshimmer .
 ```
 and then run it with
 ```
-docker run --rm -it -v target/mainnetdb:/root/mainnetdb iotaledger/goshimmer
+docker run --rm -it -v "$(pwd)/mainnetdb:/app/mainnetdb" iotaledger/goshimmer
 ```
-You may replace `target/mainnetdb` with a custom path to the database folder.
+You may replace `$(pwd)/mainnetdb` with a custom path to the database folder.
 
 To start Shimmer in the background, you can also simply use [Docker Compose](https://docs.docker.com/compose/) by running
 ```