overview of how cyber-dojo's language docker-containers work

When you set up your cyber-dojo cyber-dojo will only offer entries whose languages/ subfolder's manifest.json file has an image_name entry that exists. For example, if cyber-dojo/languages/Java/JUnit/manifest.json contains this...

{ "image_name": "cyberdojofoundation/java_junit" "display_name": "Java, JUnit", ... }

then [Java, JUnit] will only be offered if the docker image cyberdojofoundation/java_junit exists on the server, as determined by running

$ docker images

cyber-dojo will start a container from the docker image_name to execute an animals cyber-dojo.sh file each time the animal presses the [test] button.