Work on doc.

doc/prepare_ros_computer.md

@@ -7,6 +7,8 @@ instructions below.
 
 You need an Ubuntu machine with Docker installed.  Tested with 18.04 and 20.04.
 
+### Install Public Repos
+
 To install the public LRS repos containing mostly messages definitions and service calls:
 ```bash
 mkdir lrs_ws
@@ -28,3 +30,18 @@ git clone https://gitlab.liu.se/lrs/lrs_srvs_tst.git
 git clone https://gitlab.liu.se/lrs/lrs_launch.git
 ```
 
+### NVIDIA drivers Docker
+
+To get nvidia graphics to work in docker see:
+- https://aiics.waraps.org/index.php/lrs-lrs_portal-notebook_instructions-docker_linux-md/
+
+or just do:
+```bash
+# Add the package repositories
+distribution=$(. /etc/os-release;echo $ID$VERSION_ID)
+curl -s -L https://nvidia.github.io/nvidia-docker/gpgkey | sudo apt-key add -
+curl -s -L https://nvidia.github.io/nvidia-docker/$distribution/nvidia-docker.list | sudo tee /etc/apt/sources.list.d/nvidia-docker.list
+
+sudo apt-get update && sudo apt-get install -y nvidia-container-toolkit
+sudo systemctl restart docker
+```
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