Add feature specs for Goals.
user
```ruby
require 'rails_helper'

feature "Goals", :truncate => true, :js => true do
  include ActionView::Helpers::NumberHelper

  describe "Index" do

    let!(:essential_category) do
      FactoryGirl.create :category, :type => 'Essential', :name => "Groceries"
    end

    let!(:flexible_category) do
      FactoryGirl.create :category, :type => 'Flexible', :name => "Eating Out"
    end

    background do
      essential_category.goal.update_attributes(:amount => 125, :period => 'Week')
      flexible_category.goal.update_attributes(:amount => 100)
    end

    before do
      visit "/goals"
    end

    it "shows the heading" do
      expect(page).to have_content "Goals"
    end

    it "shows the category type headings" do
      expect(page).to have_content "Essential"
      expect(page).to have_content "Flexible"
    end

    it "shows the category names" do
      expect(page).to have_content "Groceries"
      expect(page).to have_content "Eating Out"
    end

    it "shows the goal amounts" do
      expect(page).to have_content number_to_currency(125 * Goal::WEEK_MULTIPLIER)
      expect(page).to have_content number_to_currency(100)
    end

    it "shows the save button" do
      expect(page).to have_button "Save"
    end
  end
end
```
assistant