Error: uninitialized constant CreateConsents::Consent

class CreateConsents < ActiveRecord::Migration
  def self.up
    create_table :consents do |t|
      t.integer :role_id, :user_id, :null => false
      t.timestamps
  end
    Role.create(:rolename => 'moderator')
    user = User.new
    user.student_no = "1274515412"
    user.username = "admin"
    user.password = "Testing12"
    user.password_confirmation = "Testing12"
    user.first_name = "Tim"
    user.last_name = "West"
    #user.grad_year = "10/02/2005"
    user.dob = "01/08/1968"
    user.email = "tim@aston.ac.uk"
    user.phone = "11545784145"
    user.photo = "image"
    #user.program = "MSc Internet Tech"
    #user.course_status = "entrolled"
    user.profession = "system admin"
    user.street = "Aston Triangle"
    user.city = "Birmingham"
    user.country = "United Kingdom"
    user.county = "west mids"
    user.post_code = "13342"
    #user.registered = "No"
    role = Role.find_by_rolename('moderator')
    user = User.find_by_username('admin')
    consent = Consent.new
    consent.role = role
    consent.user = user
    consent.save(false)
  end

  def self.down
    drop_table :consents
    Role.find_by_rolename('moderator').destroy
    User.find_by_username('admin').destroy
  end
end