Add README for GPU support

Author: huebner-m

gpu_support/README.md

@@ -0,0 +1,10 @@
+# How to add GPU support
+The collection of scripts in this directory enables you to add GPU support to your setup.
+Note that currently this means that CUDA support can be added for Nvidia GPUs. AMD GPUs are not yet supported (feel free to contribute that though!).
+To enable the usage of CUDA in your setup, simply run the following script:
+```
+./add_nvidia_gpu_support.sh
+```
+## Prerequisites and tips
+* You need write permissions to `/cvmfs/pilot.eessi-hpc.org/host_injections` (which by default is a symlink to `/opt/eessi` but can be configured in your CVMFS config file to point somewhere else). If you would like to make a system-wide installation you should change this in your configuration to point somewhere on a shared filesystem.
+* If you want to install CUDA on a node without GPUs (e.g. on a login node where you want to be able to compile your CUDA-enabled code), you should `export INSTALL_WO_GPU=true` in order to skip checks and tests that can only succeed if you have access to a GPU.