pendulum: installation fails: "ade --rc pendulum_ws/src/pendulum/ade/.aderc start --update --enter" command fails

Describe the bug Hello, thanks in first place for building this ROS2 RT example. I followed the installation instructions, but for some reason in the following steps the following command fails:

$ ade --rc pendulum_ws/src/pendulum/ade/.aderc start --update --enter" 

with following error:

OCI runtime exec failed: exec failed: container_linux.go:367: starting container process caused: chdir to cwd ("/root/ros2_foxy") set in config.json failed: permission denied: unknown
ERROR: Command return non-zero exit code (see above): 126
  docker exec -ti --env COLORFGBG --env TERM -u <myusr> ade bash -li

UPDATE: I found that the error happens on the docker exec due to the -u <myuser> without this parameter the command works. I’m quite new with docker and ade, how can I fix this command? Thank you!

To Reproduce Steps to reproduce the behavior: Followed install instructions installing in user home […]:

$ cd ~

$ mkdir adehome
$ cd adehome
$ touch .adehome

$ cd ~

$ cd /adehome
$ mkdir -p pendulum_ws/src
$ cd pendulum_ws/src
$ git clone git@github.com:ros2-realtime-demo/pendulum.git

$ cd ~

$ cd adehome
$ ade --rc pendulum_ws/src/pendulum/ade/.aderc start --update --enter

Expected behavior ade docker instance starts

Screenshots

myusr@myusr-ubuntu:~/adehome$ ade --rc pendulum_ws/src/pendulum/ade/.aderc start --update --enter
INFO: Using non-default pendulum_ws/src/pendulum/ade/.aderc configuration file
ade-base-foxy: Pulling from ros2realtimedemo/pendulum
Digest: sha256:17a2da59473d1bcb5dc0f6c5dd79a189078685f4dc2be350c644c0294867c9f4
Status: Image is up to date for ros2realtimedemo/pendulum:ade-base-foxy
docker.io/ros2realtimedemo/pendulum:ade-base-foxy
Starting ade with the following images:
pendulum | n/a | ade-base-foxy | ros2realtimedemo/pendulum:ade-base-foxy
Stopping ade
non-network local connections being added to access control list

Current default time zone: 'Europe/Berlin'
Local time is now:      Tue Apr 13 16:14:38 CEST 2021.
Universal Time is now:  Tue Apr 13 14:14:38 UTC 2021.

Adding user myusr to group video
Adding user myusr to group tracing
ADE startup completed.
Entering ade with following images:
pendulum | n/a | ade-base-foxy | ros2realtimedemo/pendulum:ade-base-foxy
OCI runtime exec failed: exec failed: container_linux.go:367: starting container process caused: chdir to cwd ("/root/ros2_foxy") set in config.json failed: permission denied: unknown
ERROR: Command return non-zero exit code (see above): 126
  docker exec -ti --env COLORFGBG --env TERM -u myusrthin ade bash -li

Desktop (please complete the following information):

• OS: Ubuntu
• Version 20.04

Additional context docker hello-world works installed ade version: 4.2.0