Build context for Fritzing on Ubuntu Bionic.
I wrote the Dockerfile based on the installation instructions in https://github.com/fritzing/fritzing-app/wiki/1.3-Linux-notes.
I uploaded the docker image to https://hub.docker.com/r/salwaelk/fritzing-bionic.
Before running the container, give docker access to Xserver: xhost +local:docker