Validation doesnt work :(

I have problem.. i have scaffold question with text field named Q... i have model answer with question_id and answer fields. i have relations -> question has_many :answers, answer -> belongs_to :question.. Ok.. I validate question -> validates_presence_of :q ... everything works..I can leave question field empty, perfect! ok next setup.. i need to answer on this question.. so i create controller answer (for user where they see only question and answer text_area field)... then i create form, everything ok.. BUT, i validate answer (in model i write -> validates_presence_of :answer), but nothing..nothing changed.. i can leave an empty field!:frowning: What do i did wrong?