Finished testing for user CRUD

Rspec testing suite incorporated
We should extract a helper for signing in since we're going to be using this in a lot of tests.

```ruby
# spec/support/helpers/authentication.rb

module Helpers
  module Authentication
    def sign_in_as(user)
      visit new_user_session_path
      fill_in "login", with: user.email
      fill_in "Password", with: user.password
      click_on "Sign in"
    end
  end
end
```

Then you can edit your `rails_helper.rb` to include those helpers in your feature specs:

```ruby
# spec/rails_helper.rb

RSpec.configure do |config|
  config.include Helpers::Authentication, type: :feature
end
```