Correction du constructeur => ne pas mettre à null les Hashset
Merge branch 'master' of https://github.com/FlavienKnuchel/Teaching-COMEM-MWS

# By Yoann Gern
# Via Yoann Gern
* 'master' of https://github.com/FlavienKnuchel/Teaching-COMEM-MWS:
  clean model

Conflicts:
	RESTBackEndSkeleton/src/main/java/ch/heigvd/skeleton/model/GroupOfPath.java