adds video_url to proposals

spec/features/proposals_spec.rb

@@ -63,6 +63,7 @@ feature 'Proposals' do
     fill_in 'proposal_summary', with: 'In summary, what we want is...'
     fill_in 'proposal_description', with: 'This is very important because...'
     fill_in 'proposal_external_url', with: 'http://rescue.org/refugees'
+    fill_in 'proposal_video_url', with: 'http://youtube.com'
     fill_in 'proposal_responsible_name', with: 'Isabel Garcia'
     fill_in 'proposal_captcha', with: correct_captcha_text
     check 'proposal_terms_of_service'
@@ -75,6 +76,7 @@ feature 'Proposals' do
     expect(page).to have_content 'In summary, what we want is...'
     expect(page).to have_content 'This is very important because...'
     expect(page).to have_content 'http://rescue.org/refugees'
+    expect(page).to have_content 'http://youtube.com'
     expect(page).to have_content author.name
     expect(page).to have_content I18n.l(Proposal.last.created_at.to_date)
   end