updated readme to include information about the run once option

Author: tobiashofmann

README.md

@@ -5,6 +5,9 @@ SAP NetWeaver ABAP Developer Edition in Docker
 
 A detailed blog on how to get this image and container up and running can be found on my blog: [DOCKERFILE FOR SAP NETWEAVER ABAP 7.5X DEVELOPER EDITION](https://www.itsfullofstars.de/2017/09/dockerfile-for-sap-netweaver-abap-7-5x-developer-edition/)
 
+To be able to setup the Docker container with just one command, make sure to read my blog [ADJUST IMAGE SIZE OF DOCKER QCOW2 FILE
+](https://www.itsfullofstars.de/2017/12/adjust-the-image-size-of-docker/). SAP NetWeaver is somewhat too large for Docker, and you can get a no space left on device error when installing it on a default Docker installation. The blog expains how to increase the Docker image file size by 100G, allowing to setup SAP NetWeaver ABAP by just running docker build -t abap .
+
 ## Short version
 
 1. Download your version of [SAP NetWeaver ABAP 7.5x Developer Edition from SAP](https://tools.hana.ondemand.com/#abap). The files are compressed (RAR). Un-compress them into a folder named NW751. The folder must be at the same location where your Dockerfile is.