How to install nbextention in jupyterhub

I manually wrote dockerfile for install nbextention on singleuser-sample
FROM jupyterhub/k8s-singleuser-sample:1.1.3
RUN pip install jupyter_contrib_nbextensions &&
pip install jupyter_nbextensions_configurator &&
jupyter contrib nbextension install --user &&
jupyter nbextensions_configurator enable --user
But it works fine as docker run single containter. But in k8s it pulls that image but nbetentions not display on tab

Hi, were you able to resolve this issue?