I realise that you specifically say Jenkins, but hopefully the following, which I've used with my students, which uses an alternative CI will be useful for some people, or possible this may be a better solution for you.
Travis CI integrates very nicely with github and with the free private repos that github provides for education you get free use of travis CI on these repositories.
Because all of my students' repositories are part of my department's github organisation (either created by Classroom or by me) I can automatically make the repository build in on Travis' own servers using the command line tool.
travis enable -r MY_ORG/student_1_repo
travis enable -r MY_ORG/student_2_repo
# etc etc ...
To make travis do something specific to each of the repos I ensure that students have specific contents in their
.travis.yml file and any other scripts they need in their repo. See this example.