There are two ways:
- The "proper" way (creates a new image). Clone the source from github, here. Edit the dockerfile to include the extra stuff you want, then build a new image, as documented on that site.
- The "quick hack" way (updates an existing running container). Execute a shell in the container with a command of the form
docker exec -it <jobe-container> /bin/bash
Then use apt-get update, apt-get install to install what you want. But if you delete the container, you lose all your additions.
Wow thanks @Richard
It worked! :-) Used the quick way
apt-get install python3-numpy at the moment.