Is it possible to run a bash script to customize a repo after starting the container?

Basically I’m just running into a permission error when starting SyncThing because root owns all of the folders. How can I run the following once the container starts without having to shell in each time I rebuild the container? I’m using Portainer for the first time also, not sure if it’s possible using it? (CE)

sudo usermod -d /home/abc
chmod 1000:1000 -R /home/abc