Cannot set default github repo during docker build

Hi all,
I'm trying to pre-load the default github repo that is shown when a docker is loaded up using the something like the following in my dockerfile (and needless to say, not working):

```
#Set up github access (this is temporary; real version will request key at container runtime)
RUN echo "c.GitHubConfig.access_token = 'ToBeReplacedWithLineInRunTimeShellScript'" >> ~/.jupyter/jupyter_notebook_config.py

RUN mkdir -p ~/.jupyter/lab/user-settings/@jupyterlab/github && \
echo "{\n "defaultRepo": "alexlicohen/script-toolbox"\n}" >> ~/.jupyter/lab/user-settings/@jupyterlab/github/drive.jupyterlab-settings
```