uninitialized constant draper

console output

[1] pry(main)> VoucherDecorator
=> VoucherDecorator
[2] pry(main)> VoucherDecorator.new
ArgumentError: wrong number of arguments (0 for 1..2)
from /usr/local/rvm/gems/ruby-2.2.1/gems/draper-2.1.0/lib/draper/decorator.rb:30:in `initialize'

gistfile1.txt

/usr/local/rvm/rubies/ruby-2.2.1/bin/ruby -I/usr/local/rvm/gems/ruby-2.2.1/gems/rspec-core-3.3.2/lib:/usr/local/rvm/gems/ruby-2.2.1/gems/rspec-support-3.3.0/lib /usr/local/rvm/gems/ruby-2.2.1/gems/rspec-core-3.3.2/exe/rspec spec/decorators/voucher_decorator_spec.rb
Coverage report generated for RSpec to /vagrant/app/coverage. 0.0 / 0.0 LOC (100.0%) covered.
/vagrant/app/spec/decorators/voucher_decorator_spec.rb:3:in `<top (required)>': uninitialized constant VoucherDecorator (NameError)
	from /usr/local/rvm/gems/ruby-2.2.1/gems/rspec-core-3.3.2/lib/rspec/core/configuration.rb:1327:in `load'
	from /usr/local/rvm/gems/ruby-2.2.1/gems/rspec-core-3.3.2/lib/rspec/core/configuration.rb:1327:in `block in load_spec_files'
	from /usr/local/rvm/gems/ruby-2.2.1/gems/rspec-core-3.3.2/lib/rspec/core/configuration.rb:1325:in `each'
	from /usr/local/rvm/gems/ruby-2.2.1/gems/rspec-core-3.3.2/lib/rspec/core/configuration.rb:1325:in `load_spec_files'
	from /usr/local/rvm/gems/ruby-2.2.1/gems/rspec-core-3.3.2/lib/rspec/core/runner.rb:102:in `setup'
	from /usr/local/rvm/gems/ruby-2.2.1/gems/rspec-core-3.3.2/lib/rspec/core/runner.rb:88:in `run'
	from /usr/local/rvm/gems/ruby-2.2.1/gems/rspec-core-3.3.2/lib/rspec/core/runner.rb:73:in `run'
	from /usr/local/rvm/gems/ruby-2.2.1/gems/rspec-core-3.3.2/lib/rspec/core/runner.rb:41:in `invoke'
	from /usr/local/rvm/gems/ruby-2.2.1/gems/rspec-core-3.3.2/exe/rspec:4:in `<main>'
/usr/local/rvm/rubies/ruby-2.2.1/bin/ruby -I/usr/local/rvm/gems/ruby-2.2.1/gems/rspec-core-3.3.2/lib:/usr/local/rvm/gems/ruby-2.2.1/gems/rspec-support-3.3.0/lib /usr/local/rvm/gems/ruby-2.2.1/gems/rspec-core-3.3.2/exe/rspec spec/decorators/voucher_decorator_spec.rb failed

voucher_decorator.rb

class VoucherDecorator < Draper::Decorator
  delegate_all

  def voucher_code
    object.voucher_code[0..3] + '-' + object.voucher_code[4..7] + '-' + object.voucer_code[8..11]
  end
end

voucher_decorator_spec.rb

require 'spec_helper'

describe VoucherDecorator do
  let(:voucher) { FactoryGirl.build(:voucher).decorate }

  it 'returns a displayable voucher code' do
    expect(voucher.voucher_code).to match /\w{3}-\w{3}-\w{3}/
  end
end