Do not allow to create a task without subproblems
Do not allow to create a task without subproblems

GuillaumeDerval/INGInious,GuillaumeDerval/INGInious,GuillaumeDerval/INGInious,layus/INGInious,layus/INGInious,layus/INGInious,GuillaumeDerval/INGInious,layus/INGInious