Update specs to new rspec syntax

spec/views/tracks/show.html.haml_spec.rb

@@ -9,7 +9,7 @@ describe 'tracks/show' do
 
   it 'displays the name of the track' do
     render
-    rendered.should have_selector('h1', text: 'Mega song')
+    expect(rendered).to have_selector 'h1', text: 'Mega song'
   end
 
   context 'when track has a sound' do
@@ -17,22 +17,22 @@ describe 'tracks/show' do
 
     it 'provides an audio stream for the track' do
       render
-      rendered.should have_selector('audio[src]')
+      expect(rendered).to have_selector 'audio[src]'
     end
 
     it 'provides controls' do
       render
-      rendered.should have_selector('audio[controls]')
+      expect(rendered).to have_selector 'audio[controls]'
     end
 
     it 'has autoplay activated' do
       render
-      rendered.should have_selector('audio[autoplay]')
+      expect(rendered).to have_selector 'audio[autoplay]'
     end
 
     it 'displays a text fallback for UA without support' do
       render
-      rendered.should have_selector(
+      expect(rendered).to have_selector(
         'audio',
         text: 'Your browser does not support the audio element'
       )