I'm trying to use Cucumber in a Rails 4. I've added the [Cucumber-Rails](https://github.com/cucumber/cucumber-rails) gem, followed the steps in the instructions but when I wrote step definitions like so:

```
When(/^I submit a sign up with the following:$/) do |table|
  user = User.create({
      first_name: 'Name',
      last_name: 'Last',
      email: 'email@example.com',
      domain: 'example.com',
      password: 'foobar',
      password_confirmation: 'foobar'
    })
end

```

I get the following error: `uninitialized constant User (NameError)
./features/step_definitions/users/sign_up_steps.rb:2:in`/^I submit a sign up with the following:$/'
features/users/sign\_up.feature:4:in `When I submit a sign up with the following:'`

What am I missing?