Update specs to new rspec syntax

spec/views/home/index.html.haml_spec.rb

@@ -12,16 +12,16 @@ describe 'home/index' do
 
   it 'displays a list of playlists' do
     render
-    rendered.should have_selector('ul>li', text: 'Electro')
+    expect(rendered).to have_selector 'ul>li', text: 'Electro'
   end
 
   it 'displays a link to add a track' do
     render
-    rendered.should have_selector('a', text: 'Add a track')
+    expect(rendered).to have_selector 'a', text: 'Add a track'
   end
 
   it 'displays a list of tracks' do
     render
-    rendered.should have_selector('ul>li', text: 'Mega song')
+    expect(rendered).to have_selector 'ul>li', text: 'Mega song'
   end
 end