Questions: fixes, redesign form, fix edit error

app/models/answer.rb

@@ -1,8 +1,21 @@
 class Answer < ActiveRecord::Base
   attr_accessible :title
 
-  has_many :qanswers
+  has_many :qanswers, dependent: :destroy
   has_many :questions, through: :qanswers
 
   validates :title, presence: true
+  validate :no_modification_if_used
+
+  def no_modification_if_used
+    errors.add('', 'cannot be altered or deleted, if they are being used.') if self.title_changed? && self.questions.any?
+  end
+
+  # Gets answer, question, conference
+  ## Returns
+  # the amount of replies for a given answer
+  # + integer +
+  def sum_replies question, conference
+    self.qanswers.find_by(question: question).registrations.where(conference: conference).count
+  end
 end