added contribution guidelines

4 jobs for master in 3 minutes and 11 seconds (queued for 8 minutes and 29 seconds)
Status Job ID Name Coverage
  Build
passed #22501
build

00:00:05

 
  Ci
passed #22503
ci_backend

00:00:43

passed #22502
ci_frontend

00:02:20

 
  Coverage
passed #22504
coverage

00:00:02

100.0%