hi i am a beginner for rails.how to write this in a model and how to call in a controller def upload @image=Image.new @image.filename=params[:image][:uploaded_data].original_filename @image.content_type=params[:image][:uploaded_data].content_type @image.siz=params[:image][:uploaded_data].size @image.user_id=params[:image][:patient_id] @image.save end