Add CI and tests

[marvinscham]

• [x] Set and enforce Rufo formatting rules
• [x] Rubocop Linting
• [ ] Automated linting on commit
• [ ] Split code into functional blocks
• [ ] Create central script to aggregate the code parts
• [ ] Add mock data
• [ ] Add tests
• [ ] Automate testing on commit
• [ ] Add code quality badges

[marvinscham]

Stale