add case choosing constraint [FORMSUB]

You can choose only case belonging to current committee

Should be field in case table in database - comittee_id which can be blank. If it's set case can be assigned only to its organization's meeting

! also adjust in zaki, trials from session should be filtered by organization

NOTE: to jest stary task ale chyba niegłupi, ogólnie obsługę case trzeba mocno dopracować