Add Capybara spec for collection
user
```ruby
require 'rails_helper'

feature 'Collection management' do
  let!(:user)    { create(:person) }
  let!(:collection)    { create(:collection, user_id: user.id) }

  background do
    user.confirmed_at = Time.now
    user.save
    sign_in(user)
  end

  describe 'Createa an unshared collection' do

    scenario 'create an unshared collection', js: true do

      # press Collections button (on the left-side tree view)
      find('div.take-ownership-btn').click

      # press Add(plus) button to add collection
      find('div.root-actions button:nth-child(2)').click

      # input collection name
      factory_collection_name = 'Hello Collection'
      new_collection = find("div#collection-management-tab-pane-1 input[value='New Collection']:last-of-type")
      new_collection.click
      new_collection.set(factory_collection_name)

      # press Update button to save
      find('div.root-actions button:nth-child(1)').click

      # except
      expect(find('.tree-view', text: factory_collection_name).text).to eq(factory_collection_name)

    end
  end

  describe 'Delete an unshared collection' do

    scenario 'delete an unshared collection', js: true do
      # byebug
      # press Collections button (on the left-side tree view)
      find('div.take-ownership-btn').click

      factory_collection_name = collection.label

      # except before deletion
      expect(page).to have_content(factory_collection_name)

      # press Delete button to delete the collection
      find("div#collection-management-tab-pane-1 button[class='btn btn-xs btn-danger']:last-of-type").click

      # press Update button to save
      find('div.root-actions button:nth-child(1)').click

      # except after deletion
      expect(page).not_to have_content(factory_collection_name)

    end
  end
end
```
assistant