Backend Unit Tests via CI & Run tests in parallel

Created by: ulfgebhardt

Pullrequest

It was a hard struggle, but I win

See: https://github.com/Ocelot-Social-Community/Ocelot-Social/actions/runs/523898450

• Backend Tests via CI
• Run CI Tasks in parallel if possible
• Docker-Tests Builds

Issues

• fixes https://github.com/Ocelot-Social-Community/Ocelot-Social/issues/4173

Todo

• Make Ticket to implement CI Cypress Tests