Add redis dump, submissions test folder to gitignore
I kept noticing the tests/data/submissions folder creeping into my workspace whenever I run
yarn test, which is inconvenient as it clutters my git directory when staging. As these files get auto-generated anyway, they should be in the gitignore.
I also have a similar issue which may be more related to my workflow, which is the redis dump.rds file. I've come across it when starting
redis-server in the root folder of zesje. As I don't think it needlessly clutters the gitignore I've also added it to the merge request.